ORCID Profile
0000-0001-7516-4016
Current Organisation
University of Sydney
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Astronomical and Space Sciences | Astronomical and Space Instrumentation | Cosmology and Extragalactic Astronomy | Galactic Astronomy | Photonics, Optoelectronics and Optical Communications | Astronomy And Astrophysics | Stellar Astronomy and Planetary Systems | Optics And Opto-Electronic Physics | Optical Physics | Instruments And Techniques | Optical And Photonic Systems | Biophysics | Communications Technologies | Other Physical Sciences | Integrated Circuits | Opthalmology And Vision Science | Data Security | Other Plasma Physics | Fluid Physics |
ANZSRC Socio-Economic Objective (SEO)
Expanding Knowledge in the Physical Sciences | Expanding Knowledge in Technology | Physical sciences | Scientific instrumentation | Scientific Instruments | Expanding Knowledge in Engineering | Telecommunications | Combined operations | Application packages | Higher education | Industrial instrumentation | Medical instrumentation | Chemical sciences | Integrated circuits and devices | Mathematical sciences | Electronic Information Storage and Retrieval Services | Food Safety
Related Links
Publications
The Large-scale Ionization Cones in the Galaxy
Publisher: American Astronomical Society
Date: 18-11-2019
Galaxy And Mass Assembly: automatic morphological classification of galaxies using statistical learning
Publisher: Oxford University Press (OUP)
Date: 20-11-2017
Near-Field Cosmology
Publisher: American Association for the Advancement of Science (AAAS)
Date: 21-07-2006
Photonic lanterns: a study of light propagation in multimode to single-mode converters
Publisher: Optica Publishing Group
Date: 07-04-2010
DOI: 10.1364/OE.18.008430
Comparison of Inverse Scattering Algorithms for Designing Ultrabroadband Fibre Bragg Gratings
Publisher: Optica Publishing Group
Date: 30-01-2009
DOI: 10.1364/OE.17.001995
Abstract: We compare different inverse scattering (IS) algorithms used to calculate profiles of fibre Bragg gratings (FBGs) and analyse their robustness, speed and implementation difficulties. We analyse sources of IS algorithm errors and discuss their relative importance. We discuss the optimal choice of IS algorithm for inverse-direct iterative optimisation schemes for grating design. We find that our time-domain layer-peeling method is an order of magnitude faster and more robust than the spectral domain algorithms considered here. We demonstrate that our method is essential to solving highly complex FBG designs demanded by astronomical applications.
Dependence of GAMA galaxy halo masses on the cosmic web environment from 100 deg2of KiDS weak lensing data
Publisher: Oxford University Press (OUP)
Date: 20-07-2016
Galaxy and Mass Assembly (GAMA): small-scale anisotropic galaxy clustering and the pairwise velocity dispersion of galaxies
Publisher: Oxford University Press (OUP)
Date: 17-11-2017
The GALAH survey and Gaia DR2: Linking ridges, arches, and vertical waves in the kinematics of the Milky Way
Publisher: Oxford University Press (OUP)
Date: 05-09-2019
Abstract: Gaia DR2 has revealed new small-scale and large-scale patterns in the phase-space distribution of stars in the Milky Way. In cylindrical Galactic coordinates $(R,\phi ,z)$, ridge-like structures can be seen in the $(R,V_\phi)$ plane and asymmetric arch-like structures in the $(V_R,V_\phi)$ plane. We show that the ridges are also clearly present when the third dimension of the $(R,V_\phi)$ plane is represented by $\langle z \rangle$, $\langle V_z \rangle$, $\langle V_R \rangle$, $\langle$[Fe/H]$\rangle$, and $\langle [\alpha /{\rm Fe}]\rangle$. The maps suggest that stars along the ridges lie preferentially close to the Galactic mid-plane ($|z|\lt 0.2$ kpc), and have metallicity and $\alpha$ elemental abundance similar to that of the Sun. We show that phase mixing of disrupting spiral arms can generate both the ridges and the arches. It also generates discrete groupings in orbital energy – the ridges and arches are simply surfaces of constant energy. We identify eight distinct ridges in the Gaia DR2 data: six of them have constant energy while two have constant angular momentum. Given that the signature is strongest for stars close to the plane, the presence of ridges in $\langle z \rangle$ and $\langle V_z \rangle$ suggests a coupling between planar and vertical directions. We demonstrate, using N-body simulations that such coupling can be generated both in isolated discs and in discs perturbed by an orbiting satellite like the Sagittarius dwarf galaxy.
The SAMI Galaxy Survey: comparing 3D spectroscopic observations with galaxies from cosmological hydrodynamical simulations
Publisher: Oxford University Press (OUP)
Date: 29-12-2019
Second generation OH suppression filters using multicore fibres
Publisher: SPIE
Date: 13-09-2012
DOI: 10.1117/12.925923
Potential applications of ring resonators for astronomical instrumentation
Publisher: SPIE
Date: 13-09-2012
DOI: 10.1117/12.925804
The Galactic Halo Ionising Field
Publisher: Cambridge University Press (CUP)
Date: 1997
DOI: 10.1071/AS97059
Abstract: There has been much debate in recent decades as to what fraction of ionising photons from star-forming regions in the Galactic disk escape into the halo. The recent detection of the Magellanic Stream in optical line emission at the CTIO 4 m and the AAT 3·9 m telescopes may now provide the strongest evidence that at least some of the radiation escapes the disk completely. We present a simple model to demonstrate that, while the distance to the Magellanic Stream is uncertain, the observed emission measures ( ε m ≈ 0·5 – 1 cm −6 pc) are most plausibly explained by photoionisation due to hot, young stars. This model requires that the mean Lyman-limit opacity perpendicular to the disk is τ LL ≈ 3, and the covering fraction of the resolved clouds is close to unity. Alternative sources (e.g. shock, halo, LMC or metagalactic radiation) contribute negligible ionising flux.
Two-phase galaxy evolution: the cosmic star formation histories of spheroids and discs
Publisher: Oxford University Press (OUP)
Date: 03-2013
DOI: 10.1093/MNRAS/STS717
Integrating the HERMES spectrograph for the AAT
Publisher: SPIE
Date: 05-10-2012
DOI: 10.1117/12.925806
Characterization of hexabundles: initial results
Publisher: Oxford University Press (OUP)
Date: 30-05-2011
The GALAH survey: verifying abundance trends in the open cluster M67 using non-LTE modelling
Publisher: Oxford University Press (OUP)
Date: 05-09-2018
Gnosis: The first instrument to use fiber bragg gratings for oh suppression
Publisher: American Astronomical Society
Date: 16-01-2013
The RAVE-on Catalog of Stellar Atmospheric Parameters and Chemical Abundances for Chemo-dynamic Studies in theGaiaEra
Publisher: American Astronomical Society
Date: 04-05-2017
The neutral hydrogen properties of galaxies in gas-rich groups
Publisher: Oxford University Press (OUP)
Date: 29-12-2018
Suppression of the near-infrared OH night-sky lines with fibre Bragg gratings - first results
Publisher: Oxford University Press (OUP)
Date: 17-08-2012
Galaxy And Mass Assembly (GAMA): Structural Investigation of Galaxies via Model Analysis
Publisher: Oxford University Press (OUP)
Date: 03-2012
Structure and Dynamics in the Local Universe: A Workshop in Honour of Brent Tully's 60th Birthday
Publisher: Cambridge University Press (CUP)
Date: 2004
DOI: 10.1071/AS04073
Abstract: We present a summary of a recent meeting held in honour of Brent Tully's 60th birthday. We also provide a retrospective on his career to date.
The large-scale distribution of warm ionized gas around nearby radio galaxies with jet-cloud interactions
Publisher: Oxford University Press (OUP)
Date: 06-2000
Identification of Globular Cluster Stars in RAVE data II: Extended tidal debris around NGC 3201
Publisher: Oxford University Press (OUP)
Date: 06-02-2016
DOI: 10.1093/MNRAS/STW083
LZIFU: an emission-line fitting toolkit for integral field spectroscopy data
Publisher: Springer Science and Business Media LLC
Date: 03-08-2016
Efficient multi-mode to single-mode coupling in a photonic lantern
Publisher: Optica Publishing Group
Date: 30-01-2009
DOI: 10.1364/OE.17.001988
Abstract: We demonstrate the fabrication of a high performance multi-mode (MM) to single-mode (SM) splitter or "photonic lantern", first described by Leon-Saval et al. (2005). Our photonic lantern is a solid all-glass version, and we show experimentally that this device can be used to achieve efficient and reversible coupling between a MM fiber and a number of SM fibers, when perfectly matched launch conditions into the MM fiber are ensured. The fabricated photonic lantern has a coupling loss for a MM to SM tapered transition of only 0.32 dB which proves the feasibility of the technology.
Wavelength-selective switch with direct few mode fiber integration
Publisher: The Optical Society
Date: 24-02-2015
DOI: 10.1364/OE.23.005723
GALAH Survey: Chemical tagging and disk reconstruction
Publisher: Wiley
Date: 09-2016
Abstract: The GALAH survey is now in its second year of a five‐year c aign to observe roughly one million stars in the southern hemisphere down to a limiting magnitude of V = 14. The project exploits the HERMES 400‐fibre échelle spectrograph at the Anglo‐Australian Telescope to measure up to 30 elemental abundances and radial velocities (≈1 km s –1 accuracy) for each star at a resolution of R = 28000. These elements fall into 8 independent groups (e.g. α , Fe peak, s‐process). For all GALAH stars, Gaia will provide distances to 1 % and transverse velocities to 1 km s –1 or better, giving us a 14D set of parameters for each star, i.e. 6D phase space and 8D abundance space. A few percent of GALAH stars will also have Kepler K2 seismological data. Here we focus on the prospect of chemically tagging the old stellar disk and making a direct measurement of how stellar migration evolves with cosmic time.
Using an artificial neural network to classify multicomponent emission lines with integral field spectroscopy from SAMI and S7
Publisher: Oxford University Press (OUP)
Date: 08-06-2017
Detecting dark matter in high-velocity clouds
Publisher: IOP Publishing
Date: 10-2000
DOI: 10.1086/316635
THE ORIGIN OF THE SPLIT RED CLUMP IN THE GALACTIC BULGE OF THE MILKY WAY
Publisher: American Astronomical Society
Date: 09-08-2012
The GALAH survey: An abundance, age, and kinematic inventory of the solar neighbourhood made with TGAS
Publisher: EDP Sciences
Date: 04-2019
DOI: 10.1051/0004-6361/201833218
Abstract: The overlap between the spectroscopic Galactic Archaeology with HERMES (GALAH) survey and Gaia provides a high-dimensional chemodynamical space of unprecedented size. We present a first analysis of a subset of this overlap, of 7066 dwarf, turn-off, and sub-giant stars. These stars have spectra from the GALAH survey and high parallax precision from the Gaia DR1 Tycho- Gaia Astrometric Solution. We investigate correlations between chemical compositions, ages, and kinematics for this s le. Stellar parameters and elemental abundances are derived from the GALAH spectra with the spectral synthesis code S PECTROSCOPY M ADE E ASY . We determine kinematics and dynamics, including action angles, from the Gaia astrometry and GALAH radial velocities. Stellar masses and ages are determined with Bayesian isochrone matching, using our derived stellar parameters and absolute magnitudes. We report measurements of Li, C, O, Na, Mg, Al, Si, K, Ca, Sc, Ti, V, Cr, Mn, Co, Ni, Cu, Zn, Y, as well as Ba and we note that we have employed non-LTE calculations for Li, O, Al, and Fe. We show that the use of astrometric and photometric data improves the accuracy of the derived spectroscopic parameters, especially log g . Focusing our investigation on the correlations between stellar age, iron abundance [Fe/H], and mean alpha-enhancement [ α /Fe] of the magnitude-selected s le, we recover the result that stars of the high- α sequence are typically older than stars in the low- α sequence, the latter spanning iron abundances of −0.7 [Fe/H] +0.5. While these two sequences become indistinguishable in [ α /Fe] vs. [Fe/H] at the metal-rich regime, we find that age can be used to separate stars from the extended high- α and the low- α sequence even in this regime. When dissecting the s le by stellar age, we find that the old stars ( Gyr) have lower angular momenta L z than the Sun, which implies that they are on eccentric orbits and originate from the inner disc. Contrary to some previous smaller scale studies we find a continuous evolution in the high- α -sequence up to super-solar [Fe/H] rather than a gap, which has been interpreted as a separate “high- α metal-rich” population. Stars in our s le that are younger than 10 Gyr, are mainly found on the low α -sequence and show a gradient in L z from low [Fe/H] ( L z L z , ⊙ ) towards higher [Fe/H] ( L z L z , ⊙ ), which implies that the stars at the ends of this sequence are likely not originating from the close solar vicinity.
ON THE SHOULDERS OF GIANTS: PROPERTIES OF THE STELLAR HALO AND THE MILKY WAY MASS DISTRIBUTION
Publisher: American Astronomical Society
Date: 24-09-2014
GALAXIA: A CODE TO GENERATE A SYNTHETIC SURVEY OF THE MILKY WAY
Publisher: American Astronomical Society
Date: 23-02-2011
KOALA: A wide-field, 1000 element integral-field unit for the Anglo-Australian Telescope
Publisher: SPIE
Date: 24-09-2012
DOI: 10.1117/12.925812
Exploring Hydrodynamic Instabilities along the Infalling High-velocity Cloud Complex A
Publisher: American Astronomical Society
Date: 23-10-2020
NanoSpec: A diffraction limited micro-spectrograph for pico- and nano-satellites
Publisher: SPIE
Date: 22-08-2012
DOI: 10.1117/12.925819
Optimization algorithm for ultrabroadband multichannel aperiodic fiber Bragg grating filters
Publisher: Optica Publishing Group
Date: 17-12-2008
Abstract: We consider an approach to designing complex multichannel filters for ultrabroadband applications. In contrast to earlier approaches that are restricted to specific problems, our generalized method can be applied to any conceivable fiber Bragg grating (FBG) multichannel design. Our method accommodates hundreds of filter channels that are spaced unevenly in wavelength, with variable widths, depths, and shapes. We demonstrate the power of the method for an FBG design with 150 narrow channels over the region 1400-1800 nm.
THE MAGELLANIC STREAM: BREAK-UP AND ACCRETION ONTO THE HOT GALACTIC CORONA
Publisher: American Astronomical Society
Date: 03-11-2015
Ionised Hydrogen at Large Galactocentric Distances
Publisher: Cambridge University Press (CUP)
Date: 1997
DOI: 10.1071/AS97064
Abstract: We summarise recent attempts to detect warm ionised gas at large galactocentric distances. This includes searches for gas at the edges of spirals, in between cluster galaxies, towards extragalactic H I clouds, and towards high-velocity clouds and the Magellanic Stream in the Galaxy. With the exception of extragalactic H I clouds, all of these experiments have proved successful. Within each class, we have only observed a handful of objects. It is premature to assess what fraction of the missing baryonic mass fraction might be in the form of ionised gas. But, in most cases, the detections provide a useful constraint on the ambient ionising flux, and, in the case of spiral edges, can even trace dark matter haloes out to radii beyond the reach of radio telescopes.
Detection of a radial velocity gradient in the extended local disc with RAVE
Publisher: Oxford University Press (OUP)
Date: 08-02-2011
Evidence of Early Enrichment of the Galactic Disk by Large-Scale Winds
Publisher: Oxford University Press (OUP)
Date: 25-04-2010
Science programs for a 2-m class telescope at dome C, antarctica: PILOT, the pathfinder for an International Large Optical Telescope
Publisher: Cambridge University Press (CUP)
Date: 2005
DOI: 10.1071/AS04077
Abstract: The cold, dry, and stable air above the summits of the Antarctic plateau provides the best ground-based observing conditions from optical to sub-millimetre wavelengths to be found on the Earth. Pathfinder for an International Large Optical Telescope (PILOT) is a proposed 2 m telescope, to be built at Dome C in Antarctica, able to exploit these conditions for conducting astronomy at optical and infrared wavelengths. While PILOT is intended as a pathfinder towards the construction of future grand-design facilities, it will also be able to undertake a range of fundamental science investigations in its own right. This paper provides the performance specifications for PILOT, including its instrumentation. It then describes the kinds of projects that it could best conduct. These range from planetary science to the search for other solar systems, from star formation within the Galaxy to the star formation history of the Universe, and from gravitational lensing caused by exo-planets to that produced by the cosmic web of dark matter. PILOT would be particularly powerful for wide-field imaging at infrared wavelengths, achieving near diffraction-limited performance with simple tip–tilt wavefront correction. PILOT would also be capable of near diffraction-limited performance in the optical wavebands, as well be able to open new wavebands for regular ground-based observation, in the mid-IR from 17 to 40 μm and in the sub-millimetre at 200 μm.
Chemical evolution with radial mixing redux: a detailed model for formation and evolution of the Milky Way
Publisher: Oxford University Press (OUP)
Date: 08-06-2023
Abstract: We present a multizone galactic chemical evolution (GCE) model for the Milky Way that takes the most recently updated yields of major nucleosynthesis channels into account. It incorporates physical processes commonly found in previous GCE models like gas feedback from supernovae and star formation, the radial flow of gas in the disc, and the infall of fresh gas, along with stellar scattering processes like radial migration. We in idually analyse the effect of different physical processes present in our model on the observed properties of the Galaxy. The radial flow of gas in the disc plays an important role in establishing the radial gradient for [Fe/H] in the low-[α/Fe] sequence. Our model with one episode of smooth gas infall and constant star formation efficiency is capable of reproducing the observed ([Fe/H], [α/Fe]) distribution of stars at different (R, |z|) positions in the Milky Way. Our results point to the rapid evolution of [α/Fe] after the onset of Type Ia supernovae and a high star formation rate during the formation of the high-[α/Fe] sequence as the origin of dual peaks in [α/Fe]. A secondary infall is unnecessary to reproduce the [α/Fe] gap and chemical spread in the disc in our model. We additionally compare the median age for various mono-abundance populations and the age–metallicity relation at different (R, |z|) positions from our fiducial model to observations. We discuss our results in relation to other related work in detail.
Modelling the Milky Way with Galaxia and making use of asteroseismology
Publisher: Wiley
Date: 09-2016
Abstract: Stellar population synthesis based models of the Milky Way play a crucial role in understanding and interpreting observational data from large surveys of the Milky Way. We describe the basic theoretical framework for modelling the Milky Way and discuss algorithms for generating a synthetic s le of stars out of such models. Next, we discuss how asteroseismology can be used to test and possibly refine theoretical models of the Milky Way. As an application we test the ability of Galaxia to reproduce the properties of stars observed by the NASA Kepler mission. We present some preliminary results. We find that Galaxia can reproduce the photometric properties of the s le. Additionally, it can also reproduce the distribution of average asteroseismic parameters and radius. In future, comparing the mass distributions will allow us to test the Galactic models more rigorously.
Where Do the Disks of Spiral Galaxies End?
Publisher: American Astronomical Society
Date: 20-11-1997
DOI: 10.1086/304865
Erratum to: The Association of Genetic Variants with Hepatic Steatosis in Patients with Genotype 1 Chronic Hepatitis C Infection
Publisher: Springer Science and Business Media LLC
Date: 12-07-2012
The SAMI Galaxy Survey: the intrinsic shape of kinematically selected galaxies
Publisher: Oxford University Press (OUP)
Date: 08-09-2017
The SAMI Galaxy Survey
Publisher: American Astronomical Society
Date: 21-07-2017
The SAMI Galaxy Survey: energy sources of the turbulent velocity dispersion in spatially resolved local star-forming galaxies
Publisher: Oxford University Press (OUP)
Date: 20-06-2017
Star–Gas Misalignment in Galaxies. I. The Properties of Galaxies from the Horizon-AGN Simulation and Comparisons to SAMI
Publisher: American Astronomical Society
Date: 12-05-2020
Hepatitis C virus selectively perturbs the distal cholesterol synthesis pathway in a genotype-specific manner
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 05-06-2012
DOI: 10.1002/HEP.25631
Abstract: Hepatitis C virus (HCV) subverts host cholesterol metabolism for key processes in its lifecycle. How this interference results in the frequently observed, genotype-dependent clinical sequelae of hypocholesterolemia, hepatic steatosis, and insulin resistance (IR) remains incompletely understood. Hypocholesterolemia typically resolves after sustained viral response (SVR), implicating viral interference in host lipid metabolism. Using a targeted cholesterol metabolomic platform we evaluated paired HCV genotype 2 (G2) and G3 patient sera for changes in in vivo HCV sterol pathway metabolites. We compared HCV genotypic differences in baseline metabolites and following antiviral treatment to assess whether sterol perturbation resolved after HCV eradication. We linked these metabolites to IR and urine oxidative stress markers. In paired sera from HCV G2 (n = 13) and G3 (n = 20) patients, baseline sterol levels were lower in G3 than G2 for distal metabolites (7-dehyrocholesterol (7DHC) 0.017 versus 0.023 mg/dL P(adj) = 0.0524, cholesterol 140.9 versus 178.7 mg/dL P(adj) = 0.0242) but not the proximal metabolite lanosterol. In HCV G3, SVR resulted in increased levels of distal metabolites (cholesterol [Δ55.2 mg/dL P(adj) = 0.0015], 7DHC [Δ0.0075 mg/dL P(adj) = 0.0026], lathosterol [Δ0.0430 mg/dL P(adj) = 0.0405]). In contrast, lanosterol was unchanged after SVR (P = 0.9515). HCV G3, but not G2, selectively interferes with the late cholesterol synthesis pathway, evidenced by lower distal sterol metabolites and preserved lanosterol levels. This distal interference resolves with SVR. Normal lanosterol levels provide a signal for the continued proteolysis of 3-hydroxyl-3-methylglutaryl coenzyme A reductase, which may undermine other host responses to increase cholesterol synthesis. These data may provide a hypothesis to explain why hypocholesterolemia persists in chronic HCV infection, particularly in HCV G3, and is not overcome by host cholesterol compensatory mechanisms.
Stellar kinematics across the Hubble sequence in the CALIFA survey: general properties and aperture corrections
Publisher: EDP Sciences
Date: 21-12-2016
The GALAH Survey: No Chemical Evidence of an Extragalactic Origin for the Nyx Stream
Publisher: American Astronomical Society
Date: 05-2021
Abstract: The results from the ESA Gaia astrometric mission and deep photometric surveys have revolutionized our knowledge of the Milky Way. There are many ongoing efforts to search these data for stellar substructure to find evidence of in idual accretion events that built up the Milky Way and its halo. One of these newly identified features, called Nyx, was announced as an accreted stellar stream traveling in the plane of the disk. Using a combination of elemental abundances and stellar parameters from the GALAH and Apache Point Observatory Galactic Evolution Experiment (APOGEE) surveys, we find that the abundances of the highest likelihood Nyx members are entirely consistent with membership of the thick disk, and inconsistent with a dwarf galaxy origin. We conclude that the postulated Nyx stream is most probably a high-velocity component of the Milky Way’s thick disk. With the growing availability of large data sets including kinematics, stellar parameters, and detailed abundances, the probability of detecting chance associations increases, and hence new searches for substructure require confirmation across as many data dimensions as possible.
Galaxy and Mass Assembly (GAMA): Exploring the WISE Web in G12
Publisher: American Astronomical Society
Date: 17-02-2017
Galaxy And Mass Assembly (GAMA): Gas Fueling of Spiral Galaxies in the Local Universe. I. The Effect of the Group Environment on Star Formation in Spiral Galaxies
Publisher: American Astronomical Society
Date: 14-02-2017
Demonstration and design of a compact diffraction limited spectrograph
Publisher: SPIE
Date: 24-09-2012
DOI: 10.1117/12.925824
GAS DEPLETION IN LOCAL GROUP DWARFS ON ∼250 kpc SCALES: RAM PRESSURE STRIPPING ASSISTED BY INTERNAL HEATING AT EARLY TIMES
Publisher: American Astronomical Society
Date: 08-04-2011
The INSPIRE-2 CubeSat for the QB50 Project
Publisher: Springer Science and Business Media LLC
Date: 26-03-2020
NGC 300: An Extremely Faint, Outer Stellar Disk Observed to 10 Scale Lengths
Publisher: American Astronomical Society
Date: 10-08-2005
DOI: 10.1086/430512
Molding the flow of light: Photonics in astronomy
Publisher: AIP Publishing
Date: 05-2012
DOI: 10.1063/PT.3.1558
Abstract: Light gathered and focused by a telescope must often be refocused onto spectrographs and other complex instruments. To such ends, astronomers are coming to realize the benefits of photonics.
Diffuse interstellar band at 8620 å in rave: A new method for detecting the diffuse interstellar band in spectra of cool stars
Publisher: American Astronomical Society
Date: 07-11-2013
Taurus Tunable Filter: A Flexible Approach to Narrowband Imaging
Publisher: Cambridge University Press (CUP)
Date: 1998
DOI: 10.1071/AS98044
Abstract: The Taurus Tunable Filter (TTF) is a tunable narrowband interference filter covering wavelengths from 6300 Å to the sensitivity drop-off of conventional CCDs (∼9600 Å), although a blue ‘arm’ (4000–6500 Å) is to be added by the end of 1997. The TTF offers monochromatic imaging at the Cassegrain foci of both the Anglo-Australian and William Herschel Telescopes, with an adjustable passband of between 6 and 60 Å. In addition, frequency switching with the TTF can be synchronised with movement of charge (charge shuffling) on the CCD, which has important applications to many astrophysical problems. Here we review the different modes of TTF and suggest their use for follow-up narrowband imaging to the AAO/UKST Galactic Plane H α Survey.
The i-INSPIRE Satellite - A university pico-satellite project
Publisher: SPIE
Date: 22-08-2012
DOI: 10.1117/12.925709
The SAMI Galaxy Survey: Spatially Resolved Metallicity and Ionization Mapping
Publisher: Oxford University Press (OUP)
Date: 05-07-2018
Galaxy And Mass Assembly (GAMA): the effect of galaxy group environment on active galactic nuclei
Publisher: Oxford University Press (OUP)
Date: 15-01-2018
DOI: 10.1093/MNRAS/STY115
PRAXIS: A near infrared spectrograph optimised for OH suppression
Publisher: SPIE
Date: 09-08-2016
DOI: 10.1117/12.2232115
The 2dF Galaxy Redshift Survey: spectral types and luminosity functions
Publisher: Oxford University Press (OUP)
Date: 19-09-1999
A Long Overdue Synthesis Image of Centaurus A
Publisher: Springer Netherlands
Date: 2008
Galaxy and Mass Assembly (GAMA): Improved emission lines measurements in four representative samples at 0.07 < z < 0.3
Publisher: EDP Sciences
Date: 28-04-2016
A spectroscopic study of the Hα surface brightness profiles in the outer discs of galaxies
Publisher: Oxford University Press (OUP)
Date: 11-05-2010
The SAMI Galaxy Survey: rules of behaviour for spin-ellipticity radial tracks in galaxies
Publisher: Oxford University Press (OUP)
Date: 12-10-2019
Abstract: We study the behaviour of the spin-ellipticity radial tracks for 507 galaxies from the Sydney AAO Multiobject Integral Field (SAMI) Galaxy Survey with stellar kinematics out to ≥1.5Re. We advocate for a morpho-dynamical classification of galaxies, relying on spatially resolved photometric and kinematic data. We find the use of spin-ellipticity radial tracks is valuable in identifying substructures within a galaxy, including embedded and counter-rotating discs, that are easily missed in unilateral studies of the photometry alone. Conversely, bars are rarely apparent in the stellar kinematics but are readily identified on images. Consequently, we distinguish the spin-ellipticity radial tracks of seven morpho-dynamical types: elliptical, lenticular, early spiral, late spiral, barred spiral, embedded disc, and 2σ galaxies. The importance of probing beyond the inner radii of galaxies is highlighted by the characteristics of galactic features in the spin-ellipticity radial tracks present at larger radii. The density of information presented through spin-ellipticity radial tracks emphasizes a clear advantage to representing galaxies as a track, rather than a single point, in spin-ellipticity parameter space.
The formation times and building blocks of Milky Way-mass galaxies in the FIRE simulations
Publisher: Oxford University Press (OUP)
Date: 06-07-2020
Abstract: Surveys of the Milky Way (MW) and M31 enable detailed studies of stellar populations across ages and metallicities, with the goal of reconstructing formation histories across cosmic time. These surveys motivate key questions for galactic archaeology in a cosmological context: When did the main progenitor of an MW/M31-mass galaxy form, and what were the galactic building blocks that formed it? We investigate the formation times and progenitor galaxies of MW/M31-mass galaxies using the Feedback In Realistic Environments-2 cosmological simulations, including six isolated MW/M31-mass galaxies and six galaxies in Local Group (LG)-like pairs at z = 0. We examine main progenitor ‘formation’ based on two metrics: (1) transition from primarily ex-situ to in-situ stellar mass growth and (2) mass dominance compared to other progenitors. We find that the main progenitor of an MW/M31-mass galaxy emerged typically at z ∼ 3–4 ($11.6\\!\\!-\\!\\!12.2\\, \\rm {Gyr}$ ago), while stars in the bulge region (inner 2 kpc) at z = 0 formed primarily in a single main progenitor at z ≲ 5 (${\\lesssim} \\!12.6\\, \\rm {Gyr}$ ago). Compared with isolated hosts, the main progenitors of LG-like paired hosts emerged significantly earlier (Δz ∼ 2, $\\Delta t\\!\\sim \\!1.6\\, \\rm {Gyr}$), with ∼4× higher stellar mass at all z ≳ 4 (${\\gtrsim} \\!12.2\\, \\rm {Gyr}$ ago). This highlights the importance of environment in MW/M31-mass galaxy formation, especially at early times. On average, about 100 galaxies with $\\rm {\\it{ M}}_\\rm {star}\\!\\gtrsim \\!10^5\\, \\rm {M}_\\odot$ went into building a typical MW/M31-mass system. Thus, surviving satellites represent a highly incomplete census (by ∼5×) of the progenitor population.
Pseudo-three-dimensional maps of the diffuse interstellar band at 862 nm
Publisher: American Association for the Advancement of Science (AAAS)
Date: 15-08-2014
Abstract: An unknown interloper systematically picks off light from galactic sources, snatching at specific wavelengths ranging from the ultraviolet to the infrared. The cause of what astronomers term diffuse interstellar bands (DIBs) still evades identification. Kos et al. combined nearly 500,000 stellar spectra from the RAVE survey to make a telling map that may clue us in further. This pseudo–three-dimensional map shows the distribution of the carrier that absorbs light at 862 nm, and it closely follows a separate map of interstellar dust, but with a significantly larger scale height in the Galactic plane. Though this is only one DIB of many, this analysis sets a path for the future study of others. Science , this issue p. 791
Comparing theoretical models of our galaxy with observations
Publisher: EDP Sciences
Date: 2012
Climbing the cosmic ladder with stellar twins in RAVE with Gaia
Publisher: Oxford University Press (OUP)
Date: 14-08-2017
THE SMITH CLOUD: HIGH-VELOCITY ACCRETION AND DARK MATTER CONFINEMENT
Publisher: American Astronomical Society
Date: 07-12-2009
The SAMI Galaxy Survey: Revising the fraction of slow rotators in IFS galaxy surveys
Publisher: Oxford University Press (OUP)
Date: 13-07-2017
The GALAH Survey: non-LTE departure coefficients for large spectroscopic surveys
Publisher: EDP Sciences
Date: 10-2020
DOI: 10.1051/0004-6361/202038650
Abstract: Massive sets of stellar spectroscopic observations are rapidly becoming available and these can be used to determine the chemical composition and evolution of the Galaxy with unprecedented precision. One of the major challenges in this endeavour involves constructing realistic models of stellar spectra with which to reliably determine stellar abundances. At present, large stellar surveys commonly use simplified models that assume that the stellar atmospheres are approximately in local thermodynamic equilibrium (LTE). To test and ultimately relax this assumption, we have performed non-LTE calculations for 13 different elements (H, Li, C, N, O, Na, Mg, Al, Si, K, Ca, Mn, and Ba), using recent model atoms that have physically-motivated descriptions for the inelastic collisions with neutral hydrogen, across a grid of 3756 1D MARCS model atmospheres that spans 3000 ≤ T eff ∕K ≤ 8000, − 0.5 ≤log g ∕cm s −2 ≤ 5.5, and − 5 ≤ [Fe/H] ≤ 1. We present the grids of departure coefficients that have been implemented into the GALAH DR3 analysis pipeline in order to complement the extant non-LTE grid for iron. We also present a detailed line-by-line re-analysis of 50 126 stars from GALAH DR3. We found that relaxing LTE can change the abundances by between − 0.7 dex and + 0.2 dex for different lines and stars. Taking departures from LTE into account can reduce the dispersion in the [A/Fe] versus [Fe/H] plane by up to 0.1 dex, and it can remove spurious differences between the dwarfs and giants by up to 0.2 dex. The resulting abundance slopes can thus be qualitatively different in non-LTE, possibly with important implications for the chemical evolution of our Galaxy. The grids of departure coefficients are publicly available and can be implemented into LTE pipelines to make the most of observational data sets from large spectroscopic surveys.
Astrophotonics: a new era for astronomical instruments
Publisher: Optica Publishing Group
Date: 30-01-2009
DOI: 10.1364/OE.17.001880
Abstract: Astrophotonics lies at the interface of astronomy and photonics. This burgeoning field has emerged over the past decade in response to the increasing demands of astronomical instrumentation. Early successes include: (i) planar waveguides to combine signals from widely spaced telescopes in stellar interferometry (ii) frequency combs for ultra-high precision spectroscopy to detect planets around nearby stars (iii) ultra-broadband fibre Bragg gratings to suppress unwanted background (iv) photonic lanterns that allow single-mode behaviour within a multimode fibre (v) planar waveguides to miniaturize astronomical spectrographs (vi) large mode area fibres to generate artificial stars in the upper atmosphere for adaptive optics correction (vii) liquid crystal polymers in optical vortex coronographs and adaptive optics systems. Astrophotonics, a field that has already created new photonic capabilities, is now extending its reach down to the Rayleigh scattering limit at ultraviolet wavelengths, and out to mid infrared wavelengths beyond 2500 nm.
The SAMI Galaxy Survey: Physical drivers of stellar-gas kinematic misalignments in the nearby Universe
Publisher: Oxford University Press (OUP)
Date: 07-10-2022
Abstract: Misalignments between the rotation axis of stars and gas are an indication of external processes shaping galaxies throughout their evolution. Using observations of 3068 galaxies from the SAMI Galaxy Survey, we compute global kinematic position angles for 1445 objects with reliable kinematics and identify 169 (12 per cent) galaxies which show stellar-gas misalignments. Kinematically decoupled features are more prevalent in early-type assive galaxies compared to late-type/star-forming systems. Star formation is the main source of gas ionization in only 22 per cent of misaligned galaxies 17 per cent are Seyfert objects, while 61 per cent show Low-Ionization Nuclear Emission-line Region features. We identify the most probable physical cause of the kinematic decoupling and find that, while accretion-driven cases are dominant, for up to 8 per cent of our s le, the misalignment may be tracing outflowing gas. When considering only misalignments driven by accretion, the acquired gas is feeding active star formation in only ∼1/4 of cases. As a population, misaligned galaxies have higher Sérsic indices and lower stellar spin and specific star formation rates than appropriately matched s les of aligned systems. These results suggest that both morphology and star formation/gas content are significantly correlated with the prevalence and timescales of misalignments. Specifically, torques on misaligned gas discs are smaller for more centrally concentrated galaxies, while the newly accreted gas feels lower viscous drag forces in more gas-poor objects. Marginal evidence of star formation not being correlated with misalignment likelihood for late-type galaxies suggests that such morphologies in the nearby Universe might be the result of preferentially aligned accretion at higher redshifts.
Galactic kinematics with RAVE data
Publisher: EDP Sciences
Date: 17-01-2008
Galaxy and mass assembly (GAMA): dust obscuration in galaxies and their recent star formation histories
Publisher: Oxford University Press (OUP)
Date: 08-11-2010
Low cost photonic comb for sub-m/s wavelength calibration
Publisher: SPIE
Date: 22-07-2016
DOI: 10.1117/12.2233678
Deep Extragalactic VIsible Legacy Survey (DEVILS): motivation,design, and target catalogue
Publisher: Oxford University Press (OUP)
Date: 14-06-2018
How does Gas Get into Galaxies?
Publisher: Springer Netherlands
Date: 2008
The SAMI Galaxy Survey
Publisher: Oxford University Press (OUP)
Date: 16-01-2018
DOI: 10.1093/MNRAS/STY127
Galaxy And Mass Assembly (GAMA): the bright void galaxy population in the optical and mid-IR
Publisher: Oxford University Press (OUP)
Date: 09-09-2015
The GALAH survey and Gaia DR2: dissecting the stellar disc’s phase space by age, action, chemistry, and location
Publisher: Oxford University Press (OUP)
Date: 22-01-2019
DOI: 10.1093/MNRAS/STZ217
A relation between the characteristic stellar ages of galaxies and their intrinsic shapes
Publisher: Springer Science and Business Media LLC
Date: 23-04-2018
Ultra-broadband High Coupling Efficiency Using a Si<inf>3</inf>N<inf>4</inf>/SiO<inf>2</inf> waveguide on silicon
Publisher: IEEE
Date: 07-2016
Galaxy And Mass Assembly (GAMA): a deeper view of the mass, metallicity and SFR relationships
Publisher: Oxford University Press (OUP)
Date: 09-07-2013
The RAVE survey: Rich in very metal-poor stars
Publisher: American Astronomical Society
Date: 02-11-2010
Wide-field dynamic astronomy in the near-infrared with Palomar Gattini-IR and DREAMS
Publisher: SPIE
Date: 03-01-2020
DOI: 10.1117/12.2539594
Inosine triphosphatase deficiency helps predict anaemia, anaemia management and response in chronic hepatitis C therapy
Publisher: Wiley
Date: 24-06-2001
DOI: 10.1111/JVH.12113
Abstract: Anaemia frequently complicates peginterferon/ribavirin therapy for chronic hepatitis C infection. Better prediction of anaemia, ribavirin dose reduction or erythropoietin (EPO) need, may enhance patient management. Inosine triphosphatase (ITPA) genetic variants are associated with ribavirin-induced anaemia and dose reduction however, their impact in real-life clinic patient cohorts remains to be defined. We studied 193 clinic patients with chronic hepatitis C infection of mixed viral genotype (genotype 1/4 n = 123, genotype 2/3, n = 70) treated with peginterferon/ribavirin. Patients were genotyped for ITPA polymorphisms rs1127354 and rs7270101 using Taqman primers. Hardy-Weinberg equilibrium was present. Estimated ITPA deficiency was graded on severity (0-3, no deficiency/mild/moderate/severe, n = 126/40/24/3, respectively). Multivariable models tested the association with anaemia at 4 weeks of treatment [including decline in haemoglobin (g/dL) haemoglobin 3 g/dL] ribavirin dose reduction and EPO use and explored sustained viral response (SVR) to peginterferon/ribavirin. More severe ITPA deficiency was associated with less reduction in haemoglobin level (P <0.001 R(2) = 0.34), less ribavirin dose reduction (OR 0.42 (95% CI = 0.23-0.77) P = 0.005) and less EPO use [OR 0.53 (0.30-0.94) P = 0.029]. ITPA deficiency was associated with SVR [OR: 1.70 (1.02-2.83) P = 0.041] independently of clinical covariates (adjusted R(2) = 0.31). In this clinical cohort, ITPA deficiency helped predict the risk of on-treatment anaemia, ribavirin dose reduction, need for EPO support and was associated with SVR. For patients on HCV regimens including peginterferon/ribavirin, testing for ITPA deficiency may have clinical utility.
The dependence of oxygen and nitrogen abundances on stellar mass from the CALIFA survey
Publisher: EDP Sciences
Date: 28-10-2016
PRAXIS - A low background NIR spectrograph for fibre Bragg grating OH suppression
Publisher: SPIE
Date: 13-09-2012
DOI: 10.1117/12.924874
A SAMI and MaNGA view on the stellar kinematics of galaxies on the star-forming main sequence
Publisher: Oxford University Press (OUP)
Date: 03-2021
Abstract: Galaxy internal structure growth has long been accused of inhibiting star formation in disc galaxies. We investigate the potential physical connection between the growth of dispersion-supported stellar structures (e.g. classical bulges) and the position of galaxies on the star-forming main sequence at z ∼ 0. Combining the might of the SAMI and MaNGA galaxy surveys, we measure the λRe spin parameter for 3289 galaxies over $9.5 \\lt \\log M_{\\star } [\\rm {M}_{\\odot }] \\lt 12$. At all stellar masses, galaxies at the locus of the main sequence possess λRe values indicative of intrinsically flattened discs. However, above $\\log M_{\\star }[\\rm {M}_{\\odot }]\\sim 10.5$ where the main sequence starts bending, we find tantalizing evidence for an increase in the number of galaxies with dispersion-supported structures, perhaps suggesting a connection between bulges and the bending of the main sequence. Moving above the main sequence, we see no evidence of any change in the typical spin parameter in galaxies once gravitationally interacting systems are excluded from the s le. Similarly, up to 1 dex below the main sequence, λRe remains roughly constant and only at very high stellar masses ($\\log M_{\\star }[\\rm {M}_{\\odot }]\\gt 11$), do we see a rapid decrease in λRe once galaxies decline in star formation activity. If this trend is confirmed, it would be indicative of different quenching mechanisms acting on high- and low-mass galaxies. The results suggest that whilst a population of galaxies possessing some dispersion-supported structure is already present on the star-forming main sequence, further growth would be required after the galaxy has quenched to match the kinematic properties observed in passive galaxies at z ∼ 0.
<title>TTF: a flexible approach to narrowband imaging</title>
Publisher: SPIE
Date: 09-07-1998
DOI: 10.1117/12.316805
TTF Survey of Galaxy Populations
Publisher: Cambridge University Press (CUP)
Date: 1997
DOI: 10.1071/AS97008
Abstract: The TAURUS Tunable Filter (TTF) affords a new approach to observational cosmology, allowing a wide field (10 arcmin) to be imaged monochromatically in contiguous wavelength intervals (6–60 Å bandpass) over the R and I bands. In a 200 s exposure with the AAT, the TTF can detect H α emission powered by star formation rates as low as 0·1 M ⊙ yr −1 at z = 0·08 and 1 M ⊙ yr −1 at z = 0·24 in 2 arcsec seeing (cf. 0·26 M ⊙ yr − 1 for the LMC). In this paper we describe an emission-line survey currently under way using the TTF on the AAT to detect redshifted H α over the ranges z = 0·06–0·1 and z = 0·22–0·26. Such detections will be of timely interest to the Southern HI Sky Survey which is motivated along similar lines.
EPISODIC STARBURSTS IN DWARF SPHEROIDAL GALAXIES: A SIMPLE MODEL
Publisher: American Astronomical Society
Date: 16-03-2012
The SAMI Galaxy Survey: reconciling strong emission line metallicity diagnostics using metallicity gradients
Publisher: Oxford University Press (OUP)
Date: 29-01-2021
Abstract: We measure the gas-phase metallicity gradients of 248 galaxies selected from Data Release 2 of the SAMI Galaxy Survey. We demonstrate that there are large systematic discrepancies between the metallicity gradients derived using common strong emission line metallicity diagnostics. We determine which pairs of diagnostics have Spearman’s rank coefficients greater than 0.6 and provide linear conversions to allow the accurate comparison of metallicity gradients derived using different strong emission line diagnostics. For galaxies within the mass range 8.5 & log (M/M⊙) & 11.0, we find discrepancies of up to 0.11 dex/Re between seven popular diagnostics in the metallicity gradient–mass relation. We find a suggestion of a break in the metallicity gradient–mass relation, where the slope shifts from negative to positive, occurs between 9.5 & log (M/M⊙) & 10.5 for the seven chosen diagnostics. Applying our conversions to the metallicity gradient–mass relation, we reduce the maximum dispersion from 0.11 dex/Re to 0.02 dex/Re. These conversions provide the most accurate method of converting metallicity gradients when key emission lines are unavailable. We find that diagnostics that share common sets of emission line ratios agree best, and that diagnostics calibrated through the electron temperature provide more consistent results compared to those calibrated through photoionization models.
PKS B1740-517: An ALMA view of the cold gas feeding a distant interacting young radio galaxy
Publisher: Oxford University Press (OUP)
Date: 24-10-2019
Tightly Correlated X‐Ray/Hα–emitting Filaments in the Superbubble and Large‐Scale Superwind of NGC 3079
Publisher: American Astronomical Society
Date: 10-09-2002
DOI: 10.1086/341861
The mysterious absence of neutral hydrogen within 1 Mpc of a luminous quasar at redshift 2.168
Publisher: Oxford University Press (OUP)
Date: 09-2004
The SAMI Galaxy Survey: Cubism and covariance, putting round pegs into square holes
Publisher: Oxford University Press (OUP)
Date: 20-11-2015
Testing formation mechanisms of the Milky Way's thick disc with RAVE
Publisher: Oxford University Press (OUP)
Date: 02-03-2011
The Smith cloud: H I associated with the Sgr dwarf?
Publisher: Oxford University Press (OUP)
Date: 09-1998
THE CALIFA AND HIPASS CIRCULAR VELOCITY FUNCTION FOR ALL MORPHOLOGICAL GALAXY TYPES
Publisher: American Astronomical Society
Date: 18-08-2016
THE RADIAL VELOCITY EXPERIMENT (RAVE): SECOND DATA RELEASE
Publisher: American Astronomical Society
Date: 13-06-2008
The SAMI Galaxy Survey: Bayesian inference for gas disc kinematics using a hierarchical Gaussian mixture model
Publisher: Oxford University Press (OUP)
Date: 08-03-2019
DOI: 10.1093/MNRAS/STZ670
Abstract: We present a novel Bayesian method, referred to as blobby3d, to infer gas kinematics that mitigates the effects of beam smearing for observations using integral field spectroscopy. The method is robust for regularly rotating galaxies despite substructure in the gas distribution. Modelling the gas substructure within the disc is achieved by using a hierarchical Gaussian mixture model. To account for beam smearing effects, we construct a modelled cube that is then convolved per wavelength slice by the seeing, before calculating the likelihood function. We show that our method can model complex gas substructure including clumps and spiral arms. We also show that kinematic asymmetries can be observed after beam smearing for regularly rotating galaxies with asymmetries only introduced in the spatial distribution of the gas. We present findings for our method applied to a s le of 20 star-forming galaxies from the SAMI Galaxy Survey. We estimate the global H α gas velocity dispersion for our s le to be in the range $\\bar{\\sigma }_v \\sim$[7, 30] km s−1. The relative difference between our approach and estimates using the single Gaussian component fits per spaxel is $\\Delta \\bar{\\sigma }_v / \\bar{\\sigma }_v = - 0.29 \\pm 0.18$ for the H α flux-weighted mean velocity dispersion.
Speciality optical fibres for astronomy
Publisher: SPIE
Date: 07-05-2015
DOI: 10.1117/12.2178427
Tunable-Filter Imaging of Quasar Fields at [CLC]z[/CLC] ∼ 1. I. A Cluster around MRC B0450−221
Publisher: American Astronomical Society
Date: 04-2001
DOI: 10.1086/319948
Focal ratio degradation in lightly fused hexabundles
Publisher: Oxford University Press (OUP)
Date: 14-12-2014
Towards a direct detection of warm gas in galactic haloes at cosmological distances
Publisher: Oxford University Press (OUP)
Date: 11-06-1999
Galactic Winds
Publisher: Annual Reviews
Date: 09-2005
DOI: 10.1146/ANNUREV.ASTRO.43.072103.150610
Abstract: ▪ Abstract Galactic winds are the primary mechanism by which energy and metals are recycled in galaxies and are deposited into the intergalactic medium. New observations are revealing the ubiquity of this process, particularly at high redshift. We describe the physics behind these winds, discuss the observational evidence for them in nearby star-forming and active galaxies and in the high-redshift universe, and consider the implications of energetic winds for the formation and evolution of galaxies and the intergalactic medium. To inspire future research, we conclude with a set of observational and theoretical challenges.
Three-dimensional simulations of a starburst-driven galactic wind
Publisher: American Astronomical Society
Date: 10-02-2008
DOI: 10.1086/524918
Radial mixing in the outer Milky Way disc caused by an orbiting satellite
Publisher: Oxford University Press (OUP)
Date: 11-08-2009
Numerical Evaluation of OH Airglow Suppression Filters
Publisher: IOP Publishing
Date: 10-1996
DOI: 10.1086/133815
Probing the Outflowing Multiphase Gas ∼1 kpc below the Galactic Center
Publisher: American Astronomical Society
Date: 23-10-2017
Near-identical star formation rate densities from Hα and FUV at redshift zero
Publisher: Oxford University Press (OUP)
Date: 12-06-2018
Very metal-poor stars observed by the RAVE survey
Publisher: EDP Sciences
Date: 07-2017
Galactic kinematics and dynamics from Radial Velocity Experiment stars
Publisher: Oxford University Press (OUP)
Date: 12-02-2014
Characterization of Low Loss Waveguides with High-Reflectivity Bragg Gratings
Publisher: OSA
Date: 2018
The Rapid Onset of Stellar Bars in the Baryon-dominated Centers of Disk Galaxies
Publisher: American Astronomical Society
Date: 04-2023
Abstract: Recent observations of high-redshift galactic disks ( z ≈ 1–3) show a strong negative trend in the dark-matter (DM) fraction f DM with increasing baryon surface density. For this to be true, the inner baryons must dominate over DM in early massive galaxies, as observed in the Milky Way today. If disks are dominant at early times, we show that stellar bars form promptly within these disks, leading to a high bar fraction. New James Webb Space Telescope observations provide the best evidence for mature stellar bars in this redshift range. The disk mass fraction f disk within R s = 2.2 R disk is the dominant factor determining how rapidly a bar forms. Using 3D hydro simulations of halo-bulge-disk galaxies, we confirm the “Fujii relation” for the exponential dependence of the bar formation time τ bar as a function of f disk . For f disk 0.3, the bar formation time declines exponentially fast with increasing f disk . Instead of Fujii's arbitrary threshold for when a bar appears, for the first time, we exploit the exponential growth timescale associated with the positive feedback cycle as the bar emerges from the underlying disk. A modified, mass-dependent trend is observed for halos relevant to systems at cosmic noon ( 10.5 log M halo 12 ), where the bar onset is slower for higher-mass halos at a fixed f disk . If baryons dominate over DM within R ≈ R s , we predict that a high fraction of bars will be found in high-redshift disks long before z = 1.
Galactic seismology: joint evolution of impact-triggered stellar and gaseous disc corrugations
Publisher: Oxford University Press (OUP)
Date: 13-07-2022
Abstract: Evidence for wave-like corrugations are well established in the Milky Way and in nearby disc galaxies. These were originally detected as a displacement of the interstellar medium about the mid-plane, either in terms of vertical distance or vertical velocity. Over the past decade, similar patterns have emerged in the Milky Way’s stellar disc. We investigate how these vertical waves are triggered by a passing satellite. Using high-resolution N-body/hydrodynamical simulations, we systematically study how the corrugations set up and evolve jointly in the stellar and gaseous discs. We find that the gas corrugations follow the stellar corrugations, i.e. they are initially in phase although, after a few rotation periods (500–700 Myr), the distinct waves separate and thereafter evolve in different ways. The spatial and kinematic litudes (and thus the energy) of the corrugations d en with time, with the gaseous corrugation settling at a faster rate (∼800 Myr versus ∼1 Gyr). In contrast, the vertical energy of in idual disc stars is fairly constant throughout the galaxy’s evolution. This difference arises because corrugations are an emergent phenomenon supported by the collective, ordered motions of co-spatial ensembles of stars. We show that the d ing of the stellar corrugations can be understood as a consequence of incomplete phase mixing, while the d ing of the gaseous corrugations is a natural consequence of the dissipative nature of the gas. We suggest that – in the absence of further, strong perturbations – the degree of correlation between the stellar and gaseous waves may help to age-date the phenomenon.
Flex (The first light explorer)—the science case for a fully oh suppressed ifu spectrograph
Publisher: Springer Netherlands
Date: 2009
New developments in integral field spectroscopy
Publisher: Springer Netherlands
Date: 2009
Galaxy and mass assembly: Redshift space distortions from the clipped galaxy field
Publisher: American Physical Society (APS)
Date: 27-01-2016
Streams on FIRE: Populations of Detectable Stellar Streams in the Milky Way and FIRE
Publisher: American Astronomical Society
Date: 25-05-2023
Abstract: We present the first detailed comparison of populations of dwarf galaxy stellar streams in cosmological simulations and the Milky Way. In particular, we compare streams identified around 13 Milky Way analogs in the FIRE-2 simulations to streams observed by the Southern Stellar Stream Spectroscopic Survey ( S 5 ). For an accurate comparison, we produce mock Dark Energy Survey (DES) observations of the FIRE streams and estimate the detectability of their tidal tails and progenitors. The number and stellar mass distributions of detectable stellar streams is consistent between observations and simulations. However, there are discrepancies in the distributions of pericenters and apocenters, with the detectable FIRE streams, on average, forming at larger pericenters (out to kpc) and surviving only at larger apocenters (≳40 kpc) than those observed in the Milky Way. We find that the population of high-stellar-mass dwarf galaxy streams in the Milky Way is incomplete. Interestingly, a large fraction of the FIRE streams would only be detected as intact satellites in DES-like observations, since their tidal tails have too low surface brightness to be detectable. We thus predict a population of yet-undetected tidal tails around Milky Way satellites, as well as a population of fully undetected low-surface-brightness stellar streams, and estimate their detectability with the Rubin Observatory. Finally, we discuss the causes and implications of the discrepancies between the stream populations in FIRE and the Milky Way, and explore future avenues for tests of satellite disruption in cosmological simulations.
The Galaxy in Context: Structural, Kinematic, and Integrated Properties
Publisher: Annual Reviews
Date: 19-09-2016
DOI: 10.1146/ANNUREV-ASTRO-081915-023441
Abstract: Our Galaxy, the Milky Way, is a benchmark for understanding disk galaxies. It is the only galaxy whose formation history can be studied using the full distribution of stars from faint dwarfs to supergiants. The oldest components provide us with unique insight into how galaxies form and evolve over billions of years. The Galaxy is a luminous (L ⋆ ) barred spiral with a central box eanut bulge, a dominant disk, and a diffuse stellar halo. Based on global properties, it falls in the sparsely populated “green valley” region of the galaxy color-magnitude diagram. Here we review the key integrated, structural and kinematic parameters of the Galaxy, and point to uncertainties as well as directions for future progress. Galactic studies will continue to play a fundamental role far into the future because there are measurements that can only be made in the near field and much of contemporary astrophysics depends on such observations.
Quantifying the (X/peanut)-shaped structure of the Milky Way – new constraints on the bar geometry
Publisher: Oxford University Press (OUP)
Date: 19-07-2017
Halo ellipticity of GAMA galaxy groups from KiDS weak lensing
Publisher: Oxford University Press (OUP)
Date: 11-02-2017
DOI: 10.1093/MNRAS/STX344
Galaxy And Mass Assembly (GAMA): stellar mass growth of spiral galaxies in the cosmic web
Publisher: Oxford University Press (OUP)
Date: 16-02-2016
DOI: 10.1093/MNRAS/STW134
<title>Rugate filters for OH-suppressed imaging</title>
Publisher: SPIE
Date: 09-07-1998
DOI: 10.1117/12.316821
Galaxy And Mass Assembly (GAMA): the galaxy stellar mass function at z < 0.06
Publisher: Oxford University Press (OUP)
Date: 02-2012
The SAMI Galaxy Survey: mass–kinematics scaling relations
Publisher: Oxford University Press (OUP)
Date: 24-05-2019
Abstract: We use data from the Sydney-AAO Multi-object Integral-field spectroscopy (SAMI) Galaxy Survey to study the dynamical scaling relation between galaxy stellar mass M∗ and the general kinematic parameter $S_K = \\sqrt{K V_{\\rm rot}^2 + \\sigma ^2}$ that combines rotation velocity Vrot and velocity dispersion σ. We show that the log M∗ – log SK relation: (1) is linear above limits set by properties of the s les and observations (2) has slightly different slope when derived from stellar or gas kinematic measurements (3) applies to both early-type and late-type galaxies and has smaller scatter than either the Tully–Fisher relation (log M∗ − log Vrot) for late types or the Faber–Jackson relation (log M∗ − log σ) for early types and (4) has scatter that is only weakly sensitive to the value of K, with minimum scatter for K in the range 0.4 and 0.7. We compare SK to the aperture second moment (the ‘aperture velocity dispersion’) measured from the integrated spectrum within a 3-arcsecond radius aperture ($\\sigma _{3^{\\prime \\prime }}$). We find that while SK and $\\sigma _{3^{\\prime \\prime }}$ are in general tightly correlated, the log M∗ − log SK relation has less scatter than the $\\log M_* - \\log \\sigma _{3^{\\prime \\prime }}$ relation.
The SAMI Galaxy Survey: the low-redshift stellar mass Tully–Fisher relation
Publisher: Oxford University Press (OUP)
Date: 19-07-2017
TheR-Process Alliance: Fourth Data Release from the Search forR-process-enhanced Stars in the Galactic Halo
Publisher: American Astronomical Society
Date: 07-08-2020
The GALAH survey: tracing the Galactic disc with open clusters
Publisher: Oxford University Press (OUP)
Date: 18-02-2021
Abstract: Open clusters are unique tracers of the history of our own Galaxy’s disc. According to our membership analysis based on Gaia astrometry, out of the 226 potential clusters falling in the footprint of the GALactic Archaeology with HERMES (GALAH) survey or the Apache Point Observatory Galactic Evolution Experiment (APOGEE) survey, we find that 205 have secure members that were observed by at least one of the surveys. Furthermore, members of 134 clusters have high-quality spectroscopic data that we use to determine their chemical composition. We leverage this information to study the chemical distribution throughout the Galactic disc of 21 elements, from C to Eu. The radial metallicity gradient obtained from our analysis is −0.076 ± 0.009 dex kpc−1, which is in agreement with previous works based on smaller s les. Furthermore, the gradient in the [Fe/H]–guiding radius (rguid) plane is −0.073 ± 0.008 dex kpc−1. We show consistently that open clusters trace the distribution of chemical elements throughout the Galactic disc differently than field stars. In particular, at the given radius, open clusters show an age–metallicity relation that has less scatter than field stars. As such scatter is often interpreted as an effect of radial migration, we suggest that these differences are due to the physical selection effect imposed by our Galaxy: clusters that would have migrated significantly also had higher chances to get destroyed. Finally, our results reveal trends in the [X/Fe]–rguid–age space, which are important to understand production rates of different elements as a function of space and time.
Starburst-driven galactic winds: Filament formation and emission processes
Publisher: American Astronomical Society
Date: 27-08-2009
Kinematics of Antlia 2 and Crater 2 from the Southern Stellar Stream Spectroscopic Survey (S 5)
Publisher: American Astronomical Society
Date: 28-10-2021
New approach to atmospheric OH suppression using an aperiodic fibre Bragg grating
Publisher: Optica Publishing Group
Date: 2004
Abstract: At near infrared wavelengths, the night sky background seen from the Earth's surface is almost completely dominated by bright spectral lines due to hydroxyl in the upper atmosphere. In the wavelength range 1- 2microm, more than 100 intrinsically narrow spectral lines account for about 98% of the sky background. Now that the performance of infrared detectors is comparable to CCDs at optical wavelengths, the bright infrared sky is the last remaining hurdle to ground-based infrared telescopes reaching sensitivity levels associated with optical telescopes. We demonstrate an aperiodic fibre Bragg grating (AFBG) which performs 94% suppression of OH emission in the 1.50-1.57microm window at a resolving power of R=10,000. This is a working prototype for a device which will allow comparable levels of OH suppression at R=50,000 across the entire near infrared (1.0-2.0microm) spectrum.
Microslit nod-shuffle spectroscopy: A technique for achieving very high densities of spectra
Publisher: IOP Publishing
Date: 02-2001
DOI: 10.1086/318625
Giant Lyα nebulae associated with high-redshift radio galaxies
Publisher: American Astronomical Society
Date: 08-2018
DOI: 10.1086/375619
The SAMI Galaxy Survey: the relationship between galaxy rotation and the motion of neighbours
Publisher: Oxford University Press (OUP)
Date: 05-07-2022
Abstract: Using data from the SAMI Galaxy Survey, we investigate the correlation between the projected stellar kinematic spin vector of 1397 SAMI galaxies and the line-of-sight motion of their neighbouring galaxies. We calculate the luminosity-weighted mean velocity difference between SAMI galaxies and their neighbours in the direction perpendicular to the SAMI galaxies’ angular momentum axes. The luminosity-weighted mean velocity offset between SAMI galaxies and neighbours, which indicates the signal of coherence between the rotation of the SAMI galaxies and the motion of neighbours, is 9.0 ± 5.4 km s−1 (1.7σ) for neighbours within 1 Mpc. In a large-scale analysis, we find that the average velocity offsets increase for neighbours out to 2 Mpc. However, the velocities are consistent with zero or negative for neighbours outside 3 Mpc. The negative signals for neighbours at a distance around 10 Mpc are also significant at the ∼2σ level, which indicate that the positive signals within 2 Mpc might come from the variance of large-scale structure. We also calculate average velocities of different subs les, including galaxies in different regions of the sky, galaxies with different stellar masses, galaxy type, λRe, and inclination. Although subs les of low-mass, high-mass, early-type, and low-spin galaxies show the 2–3σ signal of coherence for the neighbours within 2 Mpc, the results for different inclination subs les and large-scale results suggest that the ∼2σ signals might result from coincidental scatter or variance of large-scale structure. Overall, the modest evidence of coherence signals for neighbouring galaxies within 2 Mpc needs to be confirmed by larger s les of observations and simulation studies.
PROBING THE FERMI BUBBLES IN ULTRAVIOLET ABSORPTION: A SPECTROSCOPIC SIGNATURE OF THE MILKY WAY'S BICONICAL NUCLEAR OUTFLOW
Publisher: American Astronomical Society
Date: 19-01-2015
EXPLORING THE DUST CONTENT OF GALACTIC WINDS WITHHERSCHEL. I. NGC 4631
Publisher: American Astronomical Society
Date: 29-04-2015
A measurement of the cosmological mass density from clustering in the 2dF Galaxy Redshift Survey
Publisher: Springer Science and Business Media LLC
Date: 03-2001
DOI: 10.1038/35065528
Galaxy And Mass Assembly (GAMA): the large-scale structure of galaxies and comparison to mock universes
Publisher: Oxford University Press (OUP)
Date: 14-12-2013
Galactic winds: a short review
Publisher: Springer Science and Business Media LLC
Date: 09-08-2007
The interstellar disk-halo connection in the spiral galaxy NGC 3079
Publisher: American Astronomical Society
Date: 05-1995
DOI: 10.1086/175681
The SAMI Galaxy Survey: the third and final data release
Publisher: Oxford University Press (OUP)
Date: 02-2021
Abstract: We have entered a new era where integral-field spectroscopic surveys of galaxies are sufficiently large to adequately s le large-scale structure over a cosmologically significant volume. This was the primary design goal of the SAMI Galaxy Survey. Here, in Data Release 3, we release data for the full s le of 3068 unique galaxies observed. This includes the SAMI cluster s le of 888 unique galaxies for the first time. For each galaxy, there are two primary spectral cubes covering the blue (370–570 nm) and red (630–740 nm) optical wavelength ranges at spectral resolving power of R = 1808 and 4304, respectively. For each primary cube, we also provide three spatially binned spectral cubes and a set of standardized aperture spectra. For each galaxy, we include complete 2D maps from parametrized fitting to the emission-line and absorption-line spectral data. These maps provide information on the gas ionization and kinematics, stellar kinematics and populations, and more. All data are available online through Australian Astronomical Optics Data Central.
Where are the most ancient stars in the Milky Way?
Publisher: Oxford University Press (OUP)
Date: 14-07-2018
THE COSMIC HISTORY OF THE SPIN OF DARK MATTER HALOS WITHIN THE LARGE-SCALE STRUCTURE
Publisher: American Astronomical Society
Date: 17-12-2012
Astrophotonics: A promising arena for silicon photonics
Publisher: SPIE
Date: 14-03-2019
DOI: 10.1117/12.2511917
Discovery of a high-z protocluster with tunable filters: the case of 6C0140+326 at z= 4.4
Publisher: Oxford University Press (OUP)
Date: 09-2011
Distance determination for RAVE stars using stellar models: III. the nature of the RAVE survey and Milky Way chemistry
Publisher: EDP Sciences
Date: 08-2011
Measurement and limitations of optical orbital angular momentum through corrected atmospheric turbulence
Publisher: The Optical Society
Date: 04-02-2016
DOI: 10.1364/OE.24.002919
The radio continuum structure of centaurus a at 1.4GHz
Publisher: American Astronomical Society
Date: 20-09-2011
An empirical formula for the distribution function of a thin exponential disc
Publisher: American Astronomical Society
Date: 06-08-2013
In Search of Cool Flow Accretion onto Galaxies: Where Does the Disk Gas End?
Publisher: American Astronomical Society
Date: 30-10-2017
The SAMI Galaxy Survey: Extraplanar gas, galactic winds and their association with star formation history
Publisher: Oxford University Press (OUP)
Date: 02-2016
DOI: 10.1093/MNRAS/STW017
Morpho-kinematic properties of field S0 bulges in the CALIFA survey
Publisher: Oxford University Press (OUP)
Date: 27-10-2017
Evolution of galactic discs: multiple patterns, radial migration, and disc outskirts
Publisher: EDP Sciences
Date: 12-2012
Shell Structure in the Fornax Dwarf Spheroidal Galaxy
Publisher: American Astronomical Society
Date: 02-2004
DOI: 10.1086/381298
Galaxy And Mass Assembly (GAMA): the halo mass of galaxy groups from maximum-likelihood weak lensing
Publisher: Oxford University Press (OUP)
Date: 19-11-2014
The SAMI Galaxy Survey: Early Data Release
Publisher: Oxford University Press (OUP)
Date: 20-11-2015
Erratum to The SAMI galaxy survey: Can we trust aperture corrections to predict star formation?
Publisher: Oxford University Press (OUP)
Date: 19-02-2016
DOI: 10.1093/MNRAS/STW381
GalaxyCount: a java calculator of galaxy counts and variances in multiband wide-field surveys to 28 AB mag
Publisher: Oxford University Press (OUP)
Date: 11-05-2007
Reconstructing Fossil Sub-structures of the Galactic Disk: Clues from Abundance Patterns of Old Open Clusters and Moving Groups
Publisher: Cambridge University Press (CUP)
Date: 2009
DOI: 10.1071/AS08019
Abstract: The long term goal of large-scale chemical tagging is to use stellar elemental abundances as a tracer of dispersed substructures of the Galactic disk. The identification of such lost stellar aggregates and the exploration of their chemical properties will be key in understanding the formation and evolution of the disk. Present day stellar structures such as open clusters and moving groups are the ideal testing grounds for the viability of chemical tagging, as they are believed to be the remnants of the original larger star-forming aggregates. Until recently, high accuracy elemental abundance studies of open clusters and moving groups having been lacking in the literature. In this paper we examine recent high resolution abundance studies of open clusters to explore the various abundance trends and reasses the prospects of large-scale chemical tagging.
A Technique for Narrowband Time Series Photometry: The X‐Ray Star V2116 Ophiuchi
Publisher: IOP Publishing
Date: 08-1998
DOI: 10.1086/316217
Spectacular trailing streamers near LMC X-1: The first evidence of a jet?
Publisher: American Astronomical Society
Date: 12-09-2007
DOI: 10.1086/522517
A Data-driven Model of Nucleosynthesis with Chemical Tagging in a Lower-dimensional Latent Space
Publisher: American Astronomical Society
Date: 11-12-2019
Galaxy And Mass Assembly (GAMA): properties and evolution of red spiral galaxies
Publisher: Oxford University Press (OUP)
Date: 26-10-2019
Abstract: We use multiwavelength data from the Galaxy And Mass Assembly (GAMA) survey to explore the cause of red optical colours in nearby (0.002 z 0.06) spiral galaxies. We show that the colours of red spiral galaxies are a direct consequence of some environment-related mechanism(s) that has removed dust and gas, leading to a lower star formation rate. We conclude that this process acts on long time-scales (several Gyr) due to a lack of morphological transformation associated with the transition in optical colour. The specific star formation rate (sSFR) and dust-to-stellar mass ratio of red spiral galaxies is found to be statistically lower than blue spiral galaxies. On the other hand, red spirals are on average 0.9 dex more massive, and reside in environments 2.6 times denser than their blue counterparts. We find no evidence of excessive nuclear activity, or higher inclination angles to support these as the major causes for the red optical colours seen in ≳47 per cent of all spirals in our s le. Furthermore, for a small subs le of our spiral galaxies that are detected in H i, we find that the SFR of gas-rich red spiral galaxies is lower by ∼1 dex than their blue counterparts.
Galaxy And Mass Assembly (GAMA): ugrizYJHK Sérsic luminosity functions and the cosmic spectral energy distribution by Hubble type
Publisher: Oxford University Press (OUP)
Date: 12-02-2014
Galaxy And Mass Assembly (GAMA): the signatures of galaxy interactions as viewed from small-scale galaxy clustering
Publisher: Oxford University Press (OUP)
Date: 23-06-2018
First demonstration of OH suppression in a high-efficiency near-infrared spectrograph
Publisher: Oxford University Press (OUP)
Date: 08-01-2020
Abstract: Ground-based near-infrared (NIR) astronomy is severely h ered by the forest of atmospheric emission lines resulting from the rovibrational decay of OH molecules in the upper atmosphere. The extreme brightness of these lines, as well as their spatial and temporal variability, makes accurate sky subtraction difficult. Selectively filtering these lines with OH suppression instruments has been a long standing goal for NIR spectroscopy. We have shown previously the efficacy of fibre Bragg gratings (FBGs) combined with photonic lanterns for achieving OH suppression. Here we report on PRAXIS, a unique NIR spectrograph that is optimized for OH suppression with FBGs. We show for the first time that OH suppression (of any kind) is possible with high overall throughput (18 per cent end-to-end), and provide ex les of the relative benefits of OH suppression.
Arrayed waveguide gratings for astronomy with multiple off-axis fibre launch
Publisher: IEEE
Date: 05-2011
Systematic study of outflows in the Local Universe using CALIFA: I. Sample selection and main properties
Publisher: Oxford University Press (OUP)
Date: 03-11-2018
Multicore optical fibres for astrophotonics
Publisher: IEEE
Date: 05-2011
Space density distribution of galaxies in the absolute magnitude – rotation velocity plane: a volume-complete Tully-Fisher relation from CALIFA stellar kinematics
Publisher: EDP Sciences
Date: 09-2016
Three-dimensional integral field observations of 10 galactic winds. I. Extended phase (≳10 Myr) of mass/energy injection before the wind blows
Publisher: American Astronomical Society
Date: 18-02-2010
THE SAMI GALAXY SURVEY: REVISITING GALAXY CLASSIFICATION THROUGH HIGH-ORDER STELLAR KINEMATICS
Publisher: American Astronomical Society
Date: 20-01-2017
Evidence for a nonuniform initial mass function in the local universe
Publisher: American Astronomical Society
Date: 04-2009
The SAMI Galaxy Survey: the link between [α/Fe] and kinematic morphology
Publisher: Oxford University Press (OUP)
Date: 03-05-2022
Abstract: We explore a s le of 1492 galaxies with measurements of the mean stellar population properties and the spin parameter proxy, $\\lambda _{R_{\\rm {e}}}$, drawn from the SAMI Galaxy Survey. We fit a global $[\\alpha /\\rm {Fe}]$–σ relation, finding that ${[\\alpha /\\rm {Fe}]}=(0.395\\pm 0.010)\\rm {log}_{10}(\\sigma)-(0.627\\pm 0.002)$. We observe an anti-correlation between the residuals $\\Delta [\\alpha /\\rm {Fe}]$ and the inclination-corrected $\\lambda _{\\, R_{\\rm {e}}}^{\\rm {\\, eo}}$, which can be expressed as ${\\Delta [\\alpha /\\rm {Fe}]}=(-0.057\\pm 0.008){\\lambda _{\\, R_{\\rm {e}}}^{\\rm {\\, eo}}}+(0.020\\pm 0.003)$. The anti-correlation appears to be driven by star-forming galaxies, with a gradient of ${\\Delta [\\alpha /\\rm {Fe}]}\\sim (-0.121\\pm 0.015){\\lambda _{\\, R_{\\rm {e}}}^{\\rm {\\, eo}}}$, although a weak relationship persists for the subs le of galaxies for which star formation has been quenched. We take this to be confirmation that disc-dominated galaxies have an extended duration of star formation. At a reference velocity dispersion of 200 km s−1, we estimate an increase in half-mass formation time from ∼0.5 Gyr to ∼1.2 Gyr from low- to high-$\\lambda _{\\, R_{\\rm {e}}}^{\\rm {\\, eo}}$ galaxies. Slow rotators do not appear to fit these trends. Their residual α-enhancement is indistinguishable from other galaxies with ${\\lambda _{\\, R_{\\rm {e}}}^{\\rm {\\, eo}}}\\lessapprox 0.4$, despite being both larger and more massive. This result shows that galaxies with ${\\lambda _{\\, R_{\\rm {e}}}^{\\rm {\\, eo}}}\\lessapprox 0.4$ experience a similar range of star formation histories, despite their different physical structure and angular momentum.
THE IMPRINTS OF THE GALACTIC BAR ON THE THICK DISK WITH RAVE
Publisher: American Astronomical Society
Date: 20-02-2015
The SAMI galaxy survey
Publisher: Oxford University Press (OUP)
Date: 03-05-2017
Writing bragg gratings in multicore fibers
Publisher: MyJove Corporation
Date: 20-04-2016
DOI: 10.3791/53326
SAMI-H i: the connection between global asymmetry in the ionized and neutral atomic hydrogen gas in galaxies
Publisher: Oxford University Press (OUP)
Date: 16-12-2022
Abstract: Observations of the neutral atomic hydrogen (${\\rm H\\, {\\small I}}$) gas in galaxies are predominantly spatially unresolved, in the form of a global ${\\rm H\\, {\\small I}}$ spectral line. There has been substantial work on quantifying asymmetry in global ${\\rm H\\, {\\small I}}$ spectra (‘global ${\\rm H\\, {\\small I}}$ asymmetry’), but due to being spatially unresolved, it remains unknown what physical regions of galaxies the asymmetry traces, and whether the other gas phases are affected. Using optical integral field spectrograph (IFS) observations from the Sydney AAO Multi-object IFS (SAMI) survey for which global ${\\rm H\\, {\\small I}}$ spectra are also available (SAMI-${\\rm H\\, {\\small I}}$), we study the connection between asymmetry in galaxies’ ionized and neutral gas reservoirs to test if and how they can help us better understand the origin of global ${\\rm H\\, {\\small I}}$ asymmetry. We reconstruct the global Hα spectral line from the IFS observations and find that while some global Hα asymmetries can arise from disturbed ionized gas kinematics, the majority of asymmetric cases are driven by the distribution of Hα-emitting gas. When compared to the ${\\rm H\\, {\\small I}}$, we find no evidence for a relationship between the global Hα and ${\\rm H\\, {\\small I}}$ asymmetry. Further, a visual inspection reveals that cases where galaxies have qualitatively similar Hα and ${\\rm H\\, {\\small I}}$ spectral profiles can be spurious, with the similarity originating from an irregular 2D Hα flux distribution. Our results highlight that comparisons between global Hα and ${\\rm H\\, {\\small I}}$ asymmetry are not straightforward, and that many global ${\\rm H\\, {\\small I}}$ asymmetries trace disturbances that do not significantly impact the central regions of galaxies.
Hierarchical Bayesian approach for estimating physical properties in nearby galaxies: Age Maps (Paper II)
Publisher: Oxford University Press (OUP)
Date: 16-11-2018
The M31/M33 tidal interaction: a hydrodynamic simulation of the extended gas distribution
Publisher: Oxford University Press (OUP)
Date: 03-02-2020
Abstract: We revisit the orbital history of the Triangulum galaxy (M33) around the Andromeda galaxy (M31) in view of the recent Gaia Data Release 2 proper motion measurements for both Local Group galaxies. Earlier studies consider highly idealized dynamical friction, but neglect the effects of dynamical mass loss. We show the latter process to be important using mutually consistent orbit integration and N-body simulations. Following this approach, we find an orbital solution that brings these galaxies to within ∼50 kpc of each other in the past, ∼6.5 Gyr ago. We explore the implications of their interaction using an N-body/hydrodynamical simulation with a focus on the origin of two prominent features: (1) M31’s Giant Stellar Stream and (2) the M31–M33 H i filament. We find that the tidal interaction does not produce a structure reminiscent of the stellar stream that survives up to the present day. In contrast, the M31–M33 H i filament is likely a fossil structure dating back to the time of the ancient encounter between these galaxies. Similarly, the observed outer disc warp in M33 may well be a relic of this past event. Our model suggests the presence of a tidally induced gas envelope around these galaxies, and the existence of a diffuse gas stream, the ‘Triangulum stream’, stretching for tens of kpc from M33 away from M31. We anticipate upcoming observations with the recently commissioned, Five-hundred-metre Aperture Spherical radio Telescope that will target the putative stream in its first years of operation.
A combined photometric and kinematic recipe for evaluating the nature of bulges using the CALIFA sample
Publisher: EDP Sciences
Date: 28-07-2017
GAMA/WiggleZ: the 1.4 GHz radio luminosity functions of high- and low-excitation radio galaxies and their redshift evolution toz= 0.75
Publisher: Oxford University Press (OUP)
Date: 20-04-2016
DOI: 10.1093/MNRAS/STW910
GALAH survey: Chemically tagging the thick disk
Publisher: EDP Sciences
Date: 2014
DOI: 10.1051/EAS/1567039
Hexabundles - imaging fibre bundles for astronomy
Publisher: IEEE
Date: 05-2011
FLEX: The first light explorer. A fully OH-suppressed near-infrared integral field spectrograph
Publisher: SPIE
Date: 12-07-2008
DOI: 10.1117/12.788527
The radial velocity experiment (RAVE): First data release
Publisher: American Astronomical Society
Date: 12-09-2006
DOI: 10.1086/506564
GNOSIS: An OH suppressing near-infrared spectrograph for astronomy using fibre Bragg gratings
Publisher: IEEE
Date: 05-2011
S 5: The Orbital and Chemical Properties of One Dozen Stellar Streams
Publisher: American Astronomical Society
Date: 03-2022
Abstract: We report the kinematic, orbital, and chemical properties of 12 stellar streams with no evident progenitors using line-of-sight velocities and metallicities from the Southern Stellar Stream Spectroscopic Survey ( S 5 ), proper motions from Gaia EDR3, and distances derived from distance tracers or the literature. This data set provides the largest homogeneously analyzed set of streams with full 6D kinematics and metallicities. All streams have heliocentric distances between ∼10 and 50 kpc. The velocity and metallicity dispersions show that half of the stream progenitors were disrupted dwarf galaxies (DGs), while the other half originated from disrupted globular clusters (GCs), hereafter referred to as DG and GC streams. Based on the mean metallicities of the streams and the mass–metallicity relation, the luminosities of the progenitors of the DG streams range between those of Carina and Ursa Major I (−9.5 ≲ M V ≲ −5.5). Four of the six GC streams have mean metallicities of [Fe/H] −2, more metal poor than typical Milky Way (MW) GCs at similar distances. Interestingly, the 300S and Jet GC streams are the only streams on retrograde orbits in our dozen-stream s le. Finally, we compare the orbital properties of the streams with known DGs and GCs in the MW, finding several possible associations. Some streams appear to have been accreted with the recently discovered Gaia–Enceladus–Sausage system, and others suggest that GCs were formed in and accreted together with the progenitors of DG streams whose stellar masses are similar to those of Draco to Carina (∼10 5 –10 6 M ⊙ ).
THE RADIAL VELOCITY EXPERIMENT (RAVE): FOURTH DATA RELEASE
Publisher: American Astronomical Society
Date: 17-10-2013
The 2df SDSS LRG and QSO survey: evolution of the luminosity function of luminous red galaxies toz= 0.6
Publisher: Oxford University Press (OUP)
Date: 21-10-2006
GAMA/H-ATLAS: common star formation rate indicators and their dependence on galaxy physical parameters
Publisher: Oxford University Press (OUP)
Date: 20-06-2016
The SAMI galaxy survey: The discovery of a luminous, low-metallicity HII complex in the dwarf galaxy GAMA J141103.98-003242.3
Publisher: Oxford University Press (OUP)
Date: 07-10-2014
Silicon Nitride Echelle Grating Spectrometer for Operation Near 1.55μm
Publisher: IEEE
Date: 09-2018
Photonic lantern mode evolution: A multicore geometry study
Publisher: IEEE
Date: 12-2010
Galaxy And Mass Assembly: evolution of the Hα luminosity function and star formation rate density up to z < 0.35
Publisher: Oxford University Press (OUP)
Date: 29-06-2013
DOI: 10.1093/MNRAS/STT890
MORE PIECES OF THE PUZZLE: CHEMISTRY AND SUBSTRUCTURES IN THE GALACTIC THICK DISK
Publisher: American Astronomical Society
Date: 06-08-2014
Kinematic groups beyond the solar neighbourhood with RAVE
Publisher: Oxford University Press (OUP)
Date: 09-08-2012
The 2dF-SDSS LRG and QSO Survey: the spectroscopic QSO catalogue
Publisher: Oxford University Press (OUP)
Date: 2009
Constraining the Galaxy's dark halo with RAVE stars
Publisher: Oxford University Press (OUP)
Date: 24-10-2014
The GALAH survey: chemical clocks
Publisher: Oxford University Press (OUP)
Date: 12-10-2022
Abstract: We present the first large-scale study that demonstrates how ages can be determined for large s les of stars through Galactic chemical evolution. Previous studies found that the elemental abundances of a star correlate directly with its age and metallicity. Using this knowledge, we derive ages for 214 577 stars in GALAH DR3 using only overall metallicities and chemical abundances. Stellar ages are estimated via the machine learning algorithm XGBoost for stars belonging to the Milky Way disc with metallicities in the range −1 & [Fe/H] & 0.5, using main-sequence turn-off stars as our training set. We find that stellar ages for the bulk of GALAH DR3 are precise to 1–2 Gyr using this method. With these ages, we replicate many recent results on the age-kinematic trends of the nearby disc, including the solar neighbourhood’s age–velocity dispersion relationship and the larger global velocity dispersion relations of the disc found using Gaia and GALAH. These results show that chemical abundance variations at a given birth radius are small, and that strong chemical tagging of stars directly to birth clusters may prove difficult with our current elemental abundance precision. Our results highlight the need to measure abundances for as many nucleosynthetic production sites as possible in order to estimate reliable ages from chemistry. Our methods open a new door into studies of the kinematic structure and evolution of the disc, as ages may potentially be estimated to a precision of 1–2 Gyr for a large fraction of stars in existing spectroscopic surveys.
Combined APOGEE-GALAH stellar catalogues using the Cannon
Publisher: Oxford University Press (OUP)
Date: 31-03-2022
Abstract: APOGEE and GALAH are two high resolution multi-object spectroscopic surveys that provide fundamental stellar parameters and multiple elemental abundance estimates for about half a million stars in the Milky Way. Both surveys observe in different wavelength regimes and use different data reduction pipelines leading to significant offsets and trends in stellar parameters and abundances for the common stars observed in both surveys. Such systematic differences/offsets in stellar parameters and abundances make it difficult to effectively utilize them to investigate Galactic abundance trends in spite of the unique advantage provided by their complementary sky coverage and different Milky Way components they observe. Hence, we use the Cannon data-driven method selecting a training set of 4418 common stars observed by both surveys. This enables the construction of two catalogues, one with the APOGEE-scaled and the other with the GALAH-scaled stellar parameters. Using repeat observations in APOGEE and GALAH, we find high precision in metallicity (∼0.02–0.4 dex) and alpha abundances (∼0.02–0.03 dex) for spectra with good signal-to-noise ratio (SNR & 80 for APOGEE and SNR & 40 for GALAH). We use open and globular clusters to validate our parameter estimates and find small scatter in metallicity (0.06 dex) and alpha abundances (0.03 dex) in APOGEE-scaled case. The final catalogues have been cross-matched with the Gaia EDR3 catalogue to enable their use to carry out detailed chemo-dynamic studies of the Milky Way from perspectives of APOGEE and GALAH.
Can radial motions in the stellar halo constrain the rate of change of mass in the Galaxy?
Publisher: Oxford University Press (OUP)
Date: 20-03-2023
Abstract: A change in the mass of the Galaxy with time will leave its imprint on the motions of the stars, with stars having radially outward (mass-loss) or inward (mass accretion) bulk motions. Here, we test the feasibility of using the mean radial motion of stars in the stellar halo to constrain the rate of change of mass in the Galaxy, e.g. due to decay of dark matter. In the lambda cold dark matter (ΛCDM) paradigm, the stellar halo is formed by accretion of satellites on to the host galaxy and its mean radial motion 〈VR〉 is eventually expected to be close to zero. But due to incomplete mixing most haloes have substructures and this can lead to non-zero 〈VR〉 in them. Using simulations, we measure the mean radial motion of stars in 13 ΛCDM stellar haloes lying in a spherical shell of radius 30 kpc. For most haloes, the shell motion is quite small, with 75 per cent of haloes having $\\langle V_\\text{R}\\rangle \\lesssim 1.2 \\:{\\rm km}\\, {\\rm s}^{-1}$. When substructures are removed by using a clustering algorithm, 〈VR〉 is reduced even further, with 75 per cent of haloes having $\\langle V_\\text{R}\\rangle \\lesssim 0.6 \\:{\\rm km}\\, {\\rm s}^{-1}$. A value of $\\langle V_\\text{R}\\rangle \\approx 0.6 \\:{\\rm km}\\, {\\rm s}^{-1}$ can be attained corresponding to a galactic mass-loss rate of 2 per cent per Gyr. We show that this can place constraints on dark matter decay parameters such as the decay lifetime and the kick velocity that is imparted to the daughter particle. The advent of all-sky stellar surveys involving millions to billions of stars is encouraging for detecting signatures of dark matter decay.
The TESS–HERMES survey data release 1: high-resolution spectroscopy of the TESS southern continuous viewing zone
Publisher: Oxford University Press (OUP)
Date: 27-10-2017
A Multi-Core Fibre Photonic Lantern-Based Spectrograph for Raman Spectroscopy
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 04-2020
Discovery of a 21 Myr old stellar population in the Orion complex
Publisher: EDP Sciences
Date: 11-2019
DOI: 10.1051/0004-6361/201834710
Abstract: Context. The Orion complex is arguably the most studied star-forming region in the Galaxy. While stars are still being born in the Orion nebula, the oldest part was believed to be no more than 13 Myr old. Aims. In order to study the full hierarchy of star formation across the Orion complex, we perform a clustering analysis of the Ori OB1a region using new stellar surveys and derive robust ages for each identified stellar aggregate. Methods. We use Gaia DR2 parameters supplemented with radial velocities from the GALAH and APOGEE surveys to perform clustering of the Ori OB1a association. Five overdensities are resolved in a six-dimensional parameter space (positions, distance, proper motions, and radial velocity). Most correspond to previously known structures (ASCC 16, 25 Orionis, ASCC 20, ASCC 21). We use Gaia DR2, Pan-STARRS1 and 2MASS photometry to fit isochrones to the colour-magnitude diagrams of the identified clusters. The ages of the clusters can thus be measured with ∼10% precision. Results. While four of the clusters have ages between 11 and 13 Myr, the ASCC 20 cluster stands out at an age of 21 ± 3 Myr. This is significantly greater than the age of any previously known component of the Orion complex. To some degree, all clusters overlap in at least one of the six phase-space dimensions. Conclusions. We argue that the formation history of the Orion complex, and its relation to the Gould belt, must be reconsidered. A significant challenge in reconstructing the history of the Ori OB1a association is to understand the impact of the newly discovered 21 Myr old population on the younger parts of the complex, including their formation.
Constraints on the Galactic bar from the Hercules stream as traced with RAVE across the Galaxy â&dagger
Publisher: EDP Sciences
Date: 03-2014
Multiphase High‐Velocity Clouds toward HE 0226−4110 and PG 0953+414
Publisher: American Astronomical Society
Date: 09-2005
DOI: 10.1086/431915
Stellar Population Synthesis-based Modeling of the Milky Way using Asteroseismology of Dwarfs and Subgiants from Kepler
Publisher: American Astronomical Society
Date: 27-01-2017
PRAXIS: An OH suppression optimised near infrared spectrograph
Publisher: SPIE
Date: 06-07-2018
DOI: 10.1117/12.2311898
The relation between chemical abundances and kinematics of the Galactic disc with RAVE
Publisher: EDP Sciences
Date: 23-04-2013
DAzLE: The dark ages z (redshift) lyman-α explorer
Publisher: SPIE
Date: 30-09-2004
DOI: 10.1117/12.551591
Coupling light into optical fibres near the diffraction limit
Publisher: SPIE
Date: 14-06-2006
DOI: 10.1117/12.670943
THE SAMI GALAXY SURVEY: TOWARD A UNIFIED DYNAMICAL SCALING RELATION FOR GALAXIES OF ALL TYPES
Publisher: American Astronomical Society
Date: 29-10-2014
Narrow band surveys and the epoch of reionization
Publisher: Springer Netherlands
Date: 2009
ARGOS – IV. The kinematics of the Milky Way bulge
Publisher: Oxford University Press (OUP)
Date: 14-05-2013
DOI: 10.1093/MNRAS/STT533
Development of high-resolution arrayed waveguide grating spectrometers for astronomical applications: first results
Publisher: SPIE
Date: 22-07-2016
DOI: 10.1117/12.2231873
Revealing the Ionization Properties of the Magellanic Stream Using Optical Emission
Publisher: American Astronomical Society
Date: 18-12-2017
The Science Case for PILOT I: Summary and Overview
Publisher: Cambridge University Press (CUP)
Date: 2009
DOI: 10.1071/AS08048
Abstract: PILOT (the Pathfinder for an International Large Optical Telescope) is a proposed 2.5-m optical/infrared telescope to be located at Dome C on the Antarctic plateau. Conditions at Dome C are known to be exceptional for astronomy. The seeing (above ∼30 m height), coherence time, and isoplanatic angle are all twice as good as at typical mid-latitude sites, while the water-vapour column, and the atmosphere and telescope thermal emission are all an order of magnitude better. These conditions enable a unique scientific capability for PILOT, which is addressed in this series of papers. The current paper presents an overview of the optical and instrumentation suite for PILOT and its expected performance, a summary of the key science goals and observational approach for the facility, a discussion of the synergies between the science goals for PILOT and other telescopes, and a discussion of the future of Antarctic astronomy. Paper II and Paper III present details of the science projects ided, respectively, between the distant Universe (i.e. studies of first light, and the assembly and evolution of structure) and the nearby Universe (i.e. studies of Local Group galaxies, the Milky Way, and the Solar System).
The disturbed outer Milky Way disc
Publisher: Oxford University Press (OUP)
Date: 15-09-2022
Abstract: The outer parts of the Milky Way’s disc are significantly out of equilibrium. Using only distances and proper motions of stars from Gaia’s Early Data Release 3, in the range |b| & 10°, 130° & ℓ & 230°, we show that for stars in the disc between around 10 and $14\, \mathrm{kpc}$ from the Galactic centre, vertical velocity is strongly dependent on the angular momentum, azimuth, and position above or below the Galactic plane. We further show how this behaviour translates into a bimodality in the velocity distribution of stars in the outer Milky Way disc. We use an N-body model of an impulse-like interaction of the Milky Way disc with a perturber similar to the Sagittarius dwarf to demonstrate that this mechanism can generate a similar disturbance. It has already been shown that this interaction can produce a phase spiral similar to that seen in the Solar neighbourhood. We argue that the details of this substructure in the outer galaxy will be highly sensitive to the timing of the perturbation or the gravitational potential of the Galaxy, and therefore may be key to disentangling the history and structure of the Milky Way.
The SAMI Galaxy Survey: understanding observations of large-scale outflows at low redshift with EAGLE simulations
Publisher: Oxford University Press (OUP)
Date: 09-09-2017
Abstract: This work presents a study of galactic outflows driven by stellar feedback. We extract main-sequence disc galaxies with stellar mass 109 ≤ M⋆/ M⊙ ≤ 5.7 × 1010 at redshift z = 0 from the highest resolution cosmological simulation of the Evolution and Assembly of GaLaxies and their Environments (EAGLE) set. Synthetic gas rotation velocity and velocity dispersion (σ) maps are created and compared to observations of disc galaxies obtained with the Sydney-AAO (Australian Astronomical Observatory) Multi-object Integral field spectrograph (SAMI), where σ-values greater than 150 km s−1 are most naturally explained by bipolar outflows powered by starburst activity. We find that the extension of the simulated edge-on (pixelated) velocity dispersion probability distribution depends on stellar mass and star formation rate surface density (ΣSFR), with low-M⋆/low-ΣSFR galaxies showing a narrow peak at low σ (∼30 km s−1) and more active, high-M⋆/high-ΣSFR galaxies reaching σ & 150 km s−1. Although supernova-driven galactic winds in the EAGLE simulations may not entrain enough gas with T & K compared to observed galaxies, we find that gas temperature is a good proxy for the presence of outflows. There is a direct correlation between the thermal state of the gas and its state of motion as described by the σ-distribution. The following equivalence relations hold in EAGLE: (i) low-σ peak ⇔ disc of the galaxy ⇔ gas with T & K (ii) high-σ tail ⇔ galactic winds ⇔ gas with T ≥105 K.
Redesign of the integrated photonic spectrograph for improved astronomical performance
Publisher: SPIE
Date: 24-09-2012
DOI: 10.1117/12.925787
Galaxy And Mass Assembly (GAMA): in search of Milky Way Magellanic Cloud analogues
Publisher: Oxford University Press (OUP)
Date: 27-06-2012
The GALAH survey: chemodynamics of the solar neighbourhood
Publisher: Oxford University Press (OUP)
Date: 11-02-2020
Abstract: We present the chemodynamic structure of the solar neighbourhood using 55 652 stars within a 500 pc volume around the Sun observed by GALAH and with astrometric parameters from Gaia DR2. We measure the velocity dispersion for all three components (vertical, radial, and tangential) and find that it varies smoothly with [Fe/H] and [α/Fe] for each component. The vertical component is especially clean, with $\\sigma _{v_z}$ increasing from a low of 10 km s−1 at solar [α/Fe] and [Fe/H] to a high of more than 50 km s−1 for more metal-poor and [α/Fe] enhanced populations. We find no evidence of a large decrease in the velocity dispersion of the highest [α/Fe] populations as claimed in surveys prior to Gaia DR2. The eccentricity distribution for local stars varies most strongly as a function of [α/Fe], where stars with [α/Fe] & 0.1 dex having generally circular orbits (e & 0.15), while the median eccentricity increases rapidly for more [α/Fe] enhanced stellar populations up to e ∼ 0.35. These [α/Fe] enhanced populations have guiding radii consistent with origins in the inner Galaxy. Of the stars with metallicities much higher than the local interstellar medium ([Fe/H] & 0.1 dex), we find that the majority have e & 0.2 and are likely observed in the solar neighbourhood through churning/migration rather than blurring effects, as the epicyclic motion for these stars is not large enough to reach the radii at which they were likely born based on their metallicity.
Kinematic modeling of the milky way using the rave and GCS stellar surveys
Publisher: American Astronomical Society
Date: 03-09-2014
The parent populations of six groups identified from chemical tagging in the solar neighbourhood
Publisher: Oxford University Press (OUP)
Date: 06-05-2015
DOI: 10.1093/MNRAS/STV806
Choirs, H i galaxy groups: catalogue and detection of star-forming dwarf group members
Publisher: Oxford University Press (OUP)
Date: 21-05-2013
DOI: 10.1093/MNRAS/STT747
The GALAH Survey: chemical tagging and chrono-chemodynamics of accreted halo stars with GALAH+ DR3 and Gaia eDR3
Publisher: Oxford University Press (OUP)
Date: 03-12-2021
Abstract: Since the advent of Gaia astrometry, it is possible to identify massive accreted systems within the Galaxy through their unique dynamical signatures. One such system, Gaia-Sausage-Enceladus (GSE), appears to be an early ‘building block’ given its virial mass $\\gt 10^{10}\\, \\mathrm{M_\\odot }$ at infall (z ∼ 1−3). In order to separate the progenitor population from the background stars, we investigate its chemical properties with up to 30 element abundances from the GALAH+ Survey Data Release 3 (DR3). To inform our choice of elements for purely chemically selecting accreted stars, we analyse 4164 stars with low-α abundances and halo kinematics. These are most different to the Milky Way stars for abundances of Mg, Si, Na, Al, Mn, Fe, Ni, and Cu. Based on the significance of abundance differences and detection rates, we apply Gaussian mixture models to various element abundance combinations. We find the most populated and least contaminated component, which we confirm to represent GSE, contains 1049 stars selected via [Na/Fe] versus [Mg/Mn] in GALAH+ DR3. We provide tables of our selections and report the chrono-chemodynamical properties (age, chemistry, and dynamics). Through a previously reported clean dynamical selection of GSE stars, including $30 \\lt \\sqrt{J_R / \\, \\mathrm{kpc\\, km\\, s^{-1}}} \\lt 55$, we can characterize an unprecedented 24 abundances of this structure with GALAH+ DR3. With our chemical selection we characterize the dynamical properties of the GSE, for ex le mean $\\sqrt{J_R / \\, \\mathrm{kpc\\, km\\, s^{-1}}} =$$26_{-14}^{+9}$. We find only $(29\\pm 1){{\\ \\rm per\\ cent}}$ of the GSE stars within the clean dynamical selection region. Our methodology will improve future studies of accreted structures and their importance for the formation of the Milky Way.
Shape of the oxygen abundance profiles in CALIFA face-on spiral galaxies
Publisher: EDP Sciences
Date: 18-02-2016
FLEX-the first light explorer: A pathfinder instrument for fibre Bragg grating OH suppression
Publisher: SPIE
Date: 12-07-2008
DOI: 10.1117/12.788629
The SAMI Galaxy Survey: A prototype data archive for Big Science exploration
Publisher: Elsevier BV
Date: 11-2015
The RAVE survey: The Galactic escape speed and the mass of the Milky Way
Publisher: EDP Sciences
Date: 02-2014
Galaxy And Mass Assembly (GAMA): Panchromatic Data Release (far-UV–far-IR) and the low-zenergy budget
Publisher: Oxford University Press (OUP)
Date: 03-12-2015
The SAMI Galaxy Survey: Data Release Two with absorption-line physics value-added products
Publisher: Oxford University Press (OUP)
Date: 31-08-2018
Identification of globular cluster stars in RAVE data – I. Application to stellar parameter calibration
Publisher: Oxford University Press (OUP)
Date: 04-06-2015
DOI: 10.1093/MNRAS/STV800
Demonstration of uniform multicore fiber Bragg gratings
Publisher: The Optical Society
Date: 12-12-2014
DOI: 10.1364/OE.22.031575
In the thick of it: Metal-poor disc stars in RAVE
Publisher: Oxford University Press (OUP)
Date: 09-07-0100
The GALAH Survey: A New Sample of Extremely Metal-poor Stars Using a Machine-learning Classification Algorithm
Publisher: American Astronomical Society
Date: 05-2022
Abstract: Extremely metal-poor (EMP) stars provide a valuable probe of early chemical enrichment in the Milky Way. Here we leverage a large s le of ∼600,000 high-resolution stellar spectra from the GALAH survey plus a machine-learning algorithm to find 54 candidates with estimated [Fe/H] ≤−3.0, six of which have [Fe/H] ≤−3.5. Our s le includes ∼20% main-sequence EMP candidates, unusually high for EMP star surveys. We find the magnitude-limited metallicity distribution function of our s le is consistent with previous work that used more complex selection criteria. The method we present has significant potential for application to the next generation of massive stellar spectroscopic surveys, which will expand the available spectroscopic data well into the millions of stars.
The case for OH suppression at near-infrared wavelengths
Publisher: Oxford University Press (OUP)
Date: 05-2008
The GALAH Survey: second data release
Publisher: Oxford University Press (OUP)
Date: 16-05-2018
The SAMI Galaxy Survey: Gravitational Potential and Surface Density Drive Stellar Populations. I. Early-type Galaxies
Publisher: American Astronomical Society
Date: 26-03-2018
In search of first light: New technologies and new ideas
Publisher: Elsevier BV
Date: 03-2006
Multi-core fiber Bragg grating developments for OH suppression
Publisher: SPIE
Date: 13-09-2012
DOI: 10.1117/12.925791
K2-HERMES II. Planet-candidate properties from K2 Campaigns 1-13
Publisher: Oxford University Press (OUP)
Date: 03-06-2020
Abstract: Accurate and precise radius estimates of transiting exoplanets are critical for understanding their compositions and formation mechanisms. To know the planet, we must know the host star in as much detail as possible. We present complete results for planet-candidate hosts from the K2-HERMES survey, which uses the HERMES multi-object spectrograph on the Anglo-Australian Telescope to obtain $R\\sim 28\\, 000$ spectra for more than 30 000 K2 stars. We present complete host-star parameters and planet-candidate radii for 224 K2 candidate planets from C1–C13. Our results cast severe doubt on 30 K2 candidates, as we derive unphysically large radii, larger than 2RJup. This work highlights the importance of obtaining accurate, precise, and self-consistent stellar parameters for ongoing large planet search programs – something that will only become more important in the coming years, as TESS begins to deliver its own harvest of exoplanets.
Coupling light into few-mode optical fibres I: The diffraction limit
Publisher: Optica Publishing Group
Date: 19-02-2007
DOI: 10.1364/OE.15.001443
Abstract: Multimode fibres are widely used in astronomy because of the ease of coupling light into them at a telescope focus. The photonics industry has given rise to a broad range of products but these are almost exclusively restricted to single-mode fibres, although some can be adapted for use in fibres that allow several modes to propagate. Now that astronomical telescopes are moving toward diffraction-limited performance through the use of adaptive optics (AO), we address the problem of coupling light into a few-mode fibre (FMF). We find that fibres with as few as ~5 guided modes share important characterisitcs with multimode fibres, in particular high coupling efficiency.We anticipate that future astronomical instruments at an AO-corrected focus will be able to exploit a broad class of photonic devices.
Constraining the quasar population with the broad-line width distribution
Publisher: Oxford University Press (OUP)
Date: 10-2008
The Sixth Data Release of the Radial Velocity Experiment (RAVE). I. Survey Description, Spectra, and Radial Velocities
Publisher: American Astronomical Society
Date: 27-07-2020
Nebular emission and the Lyman continuum photon escape fraction in CALIFA early-type galaxies
Publisher: EDP Sciences
Date: 07-2013
Galaxy And Mass Assembly (GAMA): galaxy close pairs, mergers and the future fate of stellar mass
Publisher: Oxford University Press (OUP)
Date: 18-09-2014
The Sixth Data Release of the Radial Velocity Experiment (Rave). II. Stellar Atmospheric Parameters, Chemical Abundances, and Distances
Publisher: American Astronomical Society
Date: 27-07-2020
The 2dF-SDSS LRG and QSO Survey: the star formation histories of luminous red galaxies
Publisher: Oxford University Press (OUP)
Date: 21-11-2006
Galaxy destruction and diffuse light in clusters
Publisher: Oxford University Press (OUP)
Date: 11-05-2000
Different higher order kinematics between star-forming and quiescent galaxies based on the SAMI, MAGPI, and LEGA-C surveys
Publisher: Oxford University Press (OUP)
Date: 21-08-2023
Galaxy and Mass Assembly (GAMA): survey diagnostics and core data release
Publisher: Oxford University Press (OUP)
Date: 02-03-2011
The Smith Cloud: Surviving a high-speed transit of the Galactic disc
Publisher: Oxford University Press (OUP)
Date: 14-10-2018
Optimizing background-limited observing during bright-Moon phases and twilight
Publisher: Oxford University Press (OUP)
Date: 03-2001
Galaxy And Mass Assembly (GAMA): AUTOZ spectral redshift measurements, confidence and errors
Publisher: Oxford University Press (OUP)
Date: 20-05-2014
DOI: 10.1093/MNRAS/STU727
THE EPOCH OF ASSEMBLY OF TWO GALAXY GROUPS: A COMPARATIVE STUDY
Publisher: American Astronomical Society
Date: 11-09-2013
Performance of a Novel PMMA Polymer Imaging Bundle for Field Acquisition and Wavefront Sensing
Publisher: Cambridge University Press (CUP)
Date: 2017
DOI: 10.1017/PASA.2017.1
Abstract: Imaging bundles provide a convenient way to translate a spatially coherent image, yet conventional imaging bundles made from silica fibre optics typically remain expensive with large losses due to poor filling factors (~40%). We present the characterisation of a novel polymer imaging bundle made from poly(methyl methacrylate) (PMMA) that is considerably cheaper and a better alternative to silica imaging bundles over short distances (~1 m from the middle to the edge of a telescope’s focal plane). The large increase in filling factor (92% for the polymer imaging bundle) outweighs the large increase in optical attenuation from using PMMA (1 dB/m) instead of silica (10 −3 dB/m). We present and discuss current and possible future multi-object applications of the polymer imaging bundle in the context of astronomical instrumentation including: field acquisition, guiding, wavefront sensing, narrow-band imaging, aperture masking, and speckle imaging. The use of PMMA limits its use in low-light applications (e.g., imaging of galaxies) however, it is possible to fabricate polymer imaging bundles from a range of polymers that are better suited to the desired science.
The SAMI Galaxy Survey: Stellar Populations of Passive Spiral Galaxies in Different Environments
Publisher: American Astronomical Society
Date: 2021
Abstract: We investigate the stellar populations of passive spiral galaxies as a function of mass and environment, using integral field spectroscopy data from the Sydney-AAO Multi-object Integral field spectrograph Galaxy Survey. Our s le consists of 52 cluster passive spirals and 18 group/field passive spirals, as well as a set of S0s used as a control s le. The age and [Z/H] estimated by measuring Lick absorption line strength indices both at the center and within 1 R e do not show a significant difference between the cluster and the field/group passive spirals. However, the field/group passive spirals with log( M ⋆ / M ⊙ ) ≳ 10.5 show decreasing [ α /Fe] along with stellar mass, which is ∼0.1 dex smaller than that of the cluster passive spirals. We also compare the stellar populations of passive spirals with S0s. In the clusters, we find that passive spirals show slightly younger age and lower [ α /Fe] than the S0s over the whole mass range. In the field/group, stellar populations show a similar trend between passive spirals and S0s. In particular, [ α /Fe] of the field/group S0s tend to be flattening with increasing mass above log( M ⋆ / M ⊙ ) ≳ 10.5, similar to the field/group passive spirals. We relate the age and [ α /Fe] of passive spirals to their mean infall time in phase space we find a positive correlation, in agreement with the prediction of numerical simulations. We discuss the environmental processes that can explain the observed trends. The results lead us to conclude that the formation of the passive spirals and their transformation into S0s may significantly depend on their environments.
Multi-scale feedback and feeding in the closest radio galaxy Centaurus A
Publisher: Springer Science and Business Media LLC
Date: 22-12-2021
SEGUE 1—A COMPRESSED STAR FORMATION HISTORY BEFORE REIONIZATION
Publisher: American Astronomical Society
Date: 09-02-2016
Performance of F2T2 tandem tunable etalon
Publisher: SPIE
Date: 14-06-2006
DOI: 10.1117/12.668774
The asymmetric drift, the local standard of rest, and implications from RAVE data
Publisher: EDP Sciences
Date: 09-2013
ARGOS – II. The Galactic bulge survey
Publisher: Oxford University Press (OUP)
Date: 04-12-2012
DOI: 10.1093/MNRAS/STS305
Abstract: We describe the motivation, field locations and stellar selection for the Abundances and Radial velocity Galactic Origins Survey (ARGOS) spectroscopic survey of 28 000 stars in the bulge and inner disc of the Milky Way galaxy across latitudes of b = −5° to −10°. The primary goal of this survey is to constrain the formation processes of the bulge and establish whether it is predominantly a merger or instability remnant. From the spectra (R = 11 000), we have measured radial velocities and determined stellar parameters, including metallicities and [α/Fe] ratios. Distances were estimated from the derived stellar parameters and about 14 000 stars are red giants within 3.5 kpc of the Galactic Centre. In this paper, we present the observations and analysis methods. Subsequent papers (III and IV) will discuss the stellar metallicity distribution and kinematics of the Galactic bulge and inner disc, and the implications for the formation of the bulge.
The SAMI galaxy survey: Mass and environment as independent drivers of galaxy dynamics
Publisher: Oxford University Press (OUP)
Date: 15-09-2021
Abstract: The kinematic morphology–density relation of galaxies is normally attributed to a changing distribution of galaxy stellar masses with the local environment. However, earlier studies were largely focused on slow rotators the dynamical properties of the overall population in relation to environment have received less attention. We use the SAMI Galaxy Survey to investigate the dynamical properties of ∼1800 early and late-type galaxies with log (M⋆/M⊙) & 9.5 as a function of mean environmental overdensity (Σ5) and their rank within a group or cluster. By classifying galaxies into fast and slow rotators, at fixed stellar mass above log (M⋆/M⊙) & 10.5, we detect a higher fraction (∼3.4σ) of slow rotators for group and cluster centrals and satellites as compared to isolated-central galaxies. We find similar results when using Σ5 as a tracer for environment. Focusing on the fast-rotator population, we also detect a significant correlation between galaxy kinematics and their stellar mass as well as the environment they are in. Specifically, by using inclination-corrected or intrinsic $\\lambda _{R_{\\rm {e}}}$ values, we find that, at fixed mass, satellite galaxies on average have the lowest $\\lambda _{\\, R_{\\rm {e}},\\rm {intr}}$, isolated-central galaxies have the highest $\\lambda _{\\, R_{\\rm {e}},\\rm {intr}}$, and group and cluster centrals lie in between. Similarly, galaxies in high-density environments have lower mean $\\lambda _{\\, R_{\\rm {e}},\\rm {intr}}$ values as compared to galaxies at low environmental density. However, at fixed Σ5, the mean $\\lambda _{\\, R_{\\rm {e}},\\rm {intr}}$ differences for low and high-mass galaxies are of similar magnitude as when varying Σ5 ($\\Delta \\lambda _{\\, R_{\\rm {e}},\\rm {intr}} \\sim 0.05$, with σrandom = 0.025, and σsyst & 0.03). Our results demonstrate that after stellar mass, environment plays a significant role in the creation of slow rotators, while for fast rotators we also detect an independent, albeit smaller, impact of mass and environment on their kinematic properties.
Focal ratio degradation: A new perspective
Publisher: SPIE
Date: 14-07-2008
DOI: 10.1117/12.788735
An Efficient Approach to Characterize Low Loss Waveguides Using Bragg Gratings
Publisher: OSA
Date: 2018
The science case for PILOT III: The nearby universe
Publisher: Cambridge University Press (CUP)
Date: 2009
DOI: 10.1071/AS08051
Abstract: PILOT (the Pathfinder for an International Large Optical Telescope) is a proposed 2.5-m optical/infrared telescope to be located at Dome C on the Antarctic plateau. The atmospheric conditions at Dome C deliver a high sensitivity, high photometric precision, wide-field, high spatial resolution, and high-cadence imaging capability to the PILOT telescope. These capabilities enable a unique scientific potential for PILOT, which is addressed in this series of papers. The current paper presents a series of projects dealing with the nearby Universe that have been identified as key science drivers for the PILOT facility. Several projects are proposed that examine stellar populations in nearby galaxies and stellar clusters in order to gain insight into the formation and evolution processes of galaxies and stars. A series of projects will investigate the molecular phase of the Galaxy and explore the ecology of star formation, and investigate the formation processes of stellar and planetary systems. Three projects in the field of exoplanet science are proposed: a search for free-floating low-mass planets and dwarfs, a program of follow-up observations of gravitational microlensing events, and a study of infrared light-curves for previously discovered exoplanets. Three projects are also proposed in the field of planetary and space science: optical and near-infrared studies aimed at characterising planetary atmospheres, a study of coronal mass ejections from the Sun, and a monitoring program searching for small-scale Low Earth Orbit satellite debris items.
MAPPING THE NUCLEAR OUTFLOW OF THE MILKY WAY: STUDYING THE KINEMATICS AND SPATIAL EXTENT OF THE NORTHERN FERMI BUBBLE
Publisher: American Astronomical Society
Date: 13-01-2017
Exploring the dust content of galactic haloes with Herschel – IV. NGC 3079
Publisher: Oxford University Press (OUP)
Date: 09-10-2021
Abstract: We present the results from an analysis of deep Herschel far-infrared (far-IR) observations of the edge-on disc galaxy NGC 3079. The point spread function-cleaned Photodetector Array Camera and Spectrometer (PACS) images at 100 and 160 µm display a 25 × 25 kpc2 X-shape structure centred on the nucleus that is similar in extent and orientation to that seen in H α, X-rays, and the far-ultraviolet. One of the dusty filaments making up this structure is detected in the Spectral and Photometric Imaging Receiver 250 µm map out to ∼25 kpc from the nucleus. The match between the far-IR filaments and those detected at other wavelengths suggests that the dusty material has been lifted out of the disc by the same large-scale galactic wind that has produced the other structures in this object. A closer look at the central 10 × 10 kpc2 region provides additional support for this scenario. The dust temperatures traced by the 100–160 µm flux ratios in this region are enhanced within a biconical region centred on the active galactic nucleus, aligned along the minor axis of the galaxy, and coincident with the well-known double-lobed cm-wave radio structure and H α–X-ray nuclear superbubbles. PACS imaging spectroscopy of the inner 6 kpc region reveals broad [C ii] 158 µm emission line profiles and OH 79 µm absorption features along the minor axis of the galaxy with widths well in excess of those expected from beam smearing of the disc rotational motion. This provides compelling evidence that the cool material traced by the [C ii] and OH features directly interacts with the nuclear ionized and relativistic outflows traced by the H α, X-ray, and radio emission.
Herschel-ATLAS/GAMA: How does the far-IR luminosity function depend on galaxy group properties?
Publisher: Oxford University Press (OUP)
Date: 18-06-2014
DOI: 10.1093/MNRAS/STU962
THE CHEMICAL EVOLUTION OF VERY METAL-POOR DAMPED LYαSYSTEMS
Publisher: American Astronomical Society
Date: 07-05-2015
Instrument science at the Anglo-Australian Observatory
Publisher: SPIE
Date: 30-09-2004
DOI: 10.1117/12.550295
Extragalactic Ionized Hydrogen in the Fornax Cluster
Publisher: American Astronomical Society
Date: 10-07-1995
DOI: 10.1086/309575
Designing ultra-narrowband interference filters
Publisher: SPIE
Date: 24-09-2004
DOI: 10.1117/12.550297
Oscillating red giants observed during campaign 1 of the Kepler K2 mission: New prospects for galactic archaeology
Publisher: American Astronomical Society
Date: 04-08-2015
Reliable stellar abundances of individual stars with the MUSE integral-field spectrograph
Publisher: Oxford University Press (OUP)
Date: 24-05-2022
Abstract: We present a novel approach to deriving stellar labels for stars observed in MUSE fields making use of data-driven machine learning methods. Taking advantage of the comparable spectral properties (resolution and wavelength coverage) of the LAMOST and MUSE instruments, we adopt the data-driven Payne (DD-Payne) model used on LAMOST observations and apply it to stars observed in MUSE fields. Remarkably, in spite of instrumental differences, according to the cross-validation of 27 LAMOST-MUSE common stars, we are able to determine stellar labels with precision better than 75K in Teff, 0.15 dex in log g, and 0.1 dex in abundances of [Fe/H], [Mg/Fe], [Si/Fe], [Ti/Fe], [C/Fe], [Ni/Fe], and [Cr/Fe] for current MUSE observations over a parameter range of 3800 & Teff & 7000 K, −1.5 & [Fe/H] & 0.5 dex. To date, MUSE has been used to target 13 000 fields across the southern sky since it was first commissioned 6 yr ago and it is unique in its ability to study dense star fields such as globular clusters or the Milky Way bulge. Our method will enable the automated determination of stellar parameters for all stars in these fields. Additionally, it opens the door for applications to data collected by other spectrographs having resolution similar to LAMOST. With the upcoming BlueMUSE and MAVIS, we will gain access to a whole new range of chemical abundances with higher precision, especially critical s-process elements, such as [Y/Fe] and [Ba/Fe], that provide key age diagnostics for stellar targets.
Three-dimensional simulations of a starburst wind
Publisher: Springer Science and Business Media LLC
Date: 05-06-2007
A Wide-Field Survey of the Fornax Dwarf Spheroidal Galaxy
Publisher: American Astronomical Society
Date: 03-2005
DOI: 10.1086/427966
The Variation of the Gas Content of Galaxy Groups and Pairs Compared to Isolated Galaxies
Publisher: American Astronomical Society
Date: 03-2022
Abstract: We measure how the atomic gas (H i ) fraction f H I = M H I M * of groups and pairs taken as single units vary with average stellar mass (〈 M * 〉) and average star formation rate (〈SFR〉), compared to isolated galaxies. The H i 21 cm emission observation are from (i) archival ALFALFA survey data covering three fields from the GAMA survey (provides environmental and galaxy properties), and (ii) DINGO pilot survey data of one of those fields. The mean f H i for different units (groups airs/isolated galaxies) are measured in regions of the log(〈 M * 〉)–log(〈SFR〉) plane, relative to the z ∼ 0 star-forming main sequence (SFMS) of in idual galaxies, by stacking f H i spectra of in idual units. For ALFALFA, f H i spectra of units are measured by extracting H i spectra over the full groups air areas and iding by the total stellar mass of member galaxies. For DINGO, f H i spectra of units are measured by co-adding H i spectra of in idual member galaxies, followed by ision by their total stellar mass. For all units, the mean f H i decreases as we move to higher 〈 M * 〉 along the SFMS and as we move from above the SFMS to below it at any 〈 M * 〉. From the DINGO-based study, mean f H i in groups appears to be lower compared to isolated galaxies for all 〈 M * 〉 along the SFMS. From the ALFALFA-based study, we find substantially higher mean f H i in groups compared to isolated galaxies (values for pairs being intermediate) for 〈 M * 〉 ≲ 10 9.5 M ⊙ , indicating the presence of substantial amounts of H i not associated with cataloged member galaxies in low mass groups.
The jet/wind outflow in Centaurus A: A local laboratory for AGN feedback
Publisher: Oxford University Press (OUP)
Date: 09-11-2018
Cosmic star formation history to z = 1 from a narrow emission line-selected tunable-filter survey
Publisher: American Astronomical Society
Date: 12-2004
DOI: 10.1086/425552
Tunable-Filter Imaging of Quasar Fields atz ~ 1. II. The Star-forming Galaxy Environments of Radio-loud Quasars
Publisher: American Astronomical Society
Date: 12-2004
DOI: 10.1086/425550
Weighing the local dark matter with RAVE red clump stars
Publisher: EDP Sciences
Date: 11-2014
Spectroscopic signatures of extratidal stars around the globular clusters NGC 6656 (M 22), NGC 3201, and NGC 1851 from RAVE
Publisher: EDP Sciences
Date: 25-11-2014
Honeycomb: a concept for a programmable integral field spectrograph
Publisher: SPIE
Date: 30-09-2004
DOI: 10.1117/12.550291
The CALIFA view on stellar angular momentum across the Hubble sequence
Publisher: EDP Sciences
Date: 28-11-2019
DOI: 10.1051/0004-6361/201936413
Abstract: We present the apparent stellar angular momentum over the optical extent of 300 galaxies across the Hubble sequence using integral-field spectroscopic (IFS) data from the CALIFA survey. Adopting the same λ R parameter previously used to distinguish between slow and fast rotating early-type (elliptical and lenticular) galaxies, we show that spiral galaxies are almost all fast rotators, as expected. Given the extent of our data, we provide relations for λ R measured in different apertures (e.g. fractions of the effective radius: 0.5 R e , R e , 2 R e ), including conversions to long-slit 1D apertures. Our s le displays a wide range of λ Re values, consistent with previous IFS studies. The fastest rotators are dominated by relatively massive and highly star-forming Sb galaxies, which preferentially reside in the main star-forming sequence. These galaxies reach λ Re values of ∼0.85, and they are the largest galaxies at a given mass, while also displaying some of the strongest stellar population gradients. Compared to the population of S0 galaxies, our findings suggest that fading may not be the dominant mechanism transforming spirals into lenticulars. Interestingly, we find that λ Re decreases for late-type Sc and Sd spiral galaxies, with values that occasionally set them in the slow-rotator regime. While for some of them this can be explained by their irregular morphologies and/or face-on configurations, others are edge-on systems with no signs of significant dust obscuration. The latter are typically at the low-mass end, but this does not explain their location in the classical ( V / σ , ε ) and ( λ Re , ε ) diagrams. Our initial investigations, based on dynamical models, suggest that these are dynamically hot disks, probably influenced by the observed important fraction of dark matter within R e .
Portable frequency combs for optical frequency metrology
Publisher: The Optical Society
Date: 09-07-2012
DOI: 10.1364/OE.20.016671
The SAMI Galaxy Survey: Bulge and Disk Stellar Population Properties in Cluster Galaxies
Publisher: American Astronomical Society
Date: 2021
Abstract: We explore stellar population properties separately in the bulge and the disk of double-component cluster galaxies, to shed light on the formation of lenticular galaxies in dense environments. We study eight low-redshift clusters from the Sydney-AAO Multi-object Integral field Galaxy Survey, using two-dimensional photometric bulge–disk decomposition in the g , r , and i bands to characterize galaxies. For 192 double-component galaxies with M * 10 10 M ⊙ , we estimate the color, age, and metallicity of the bulge and the disk. The analysis of the g − i colors reveals that bulges are redder than their surrounding disks, with a median offset of 0.12 ± 0.02 mag, consistent with previous results. To measure mass-weighted age and metallicity, we investigate three methods: (i) one based on galaxy stellar mass weights for the two components, (ii) one based on flux weights, and (iii) one based on radial separation. The three methods agree in finding 62% of galaxies having bulges that are 2–3 times more metal-rich than the disks. Of the remaining galaxies, 7% have bulges that are more metal-poor than the disks, while for 31%, the bulge and disk metallicities are not significantly different. We observe 23% of galaxies being characterized by bulges older and 34% by bulges younger with respect to the disks. The remaining 43% of galaxies have bulges and disks with statistically indistinguishable ages. Redder bulges tend to be more metal-rich than the disks, suggesting that the redder color in bulges is due to their enhanced metallicity relative to the disks instead of differences in stellar population age.
The Galah Survey: Classification and Diagnostics with t-SNE Reduction of Spectral Information
Publisher: American Astronomical Society
Date: 23-02-2017
A search for new members of the βPictoris, Tucana-Horologium and εCha moving groups in the RAVE data base
Publisher: Oxford University Press (OUP)
Date: 21-10-2011
The SAMI Galaxy Survey
Publisher: Oxford University Press (OUP)
Date: 08-08-2016
The GALAH Survey: Chemically tagging the Fimbulthul stream to the globular cluster ω Centauri
Publisher: Oxford University Press (OUP)
Date: 05-11-2020
Abstract: Using kinematics from Gaia and the large elemental abundance space of the second data release of the GALAH survey, we identify two new members of the Fimbulthul stellar stream, and chemically tag them to massive, multimetallic globular cluster ω Centauri. Recent analysis of the second data release of Gaia had revealed the Fimbulthul stellar stream in the halo of the Milky Way. It had been proposed that the stream is associated with the ω Cen, but this proposition relied exclusively upon the kinematics and metallicities of the stars to make the association. In this work, we find our two new members of the stream to be metal-poor stars that are enhanced in sodium and aluminium, typical of second population globular cluster stars, but not otherwise seen in field stars. Furthermore, the stars share the s-process abundance pattern seen in ω Cen, which is rare in field stars. Apart from one star within 1.5 deg of ω Cen, we find no other stars observed by GALAH spatially near ω Cen or the Fimbulthul stream that could be kinematically and chemically linked to the cluster. Chemically tagging stars in the Fimbulthul stream to ω Cen confirms the earlier work, and further links this tidal feature in the Milky Way halo to ω Cen.
The K2-HERMES Survey. I. Planet-candidate Properties from K2 Campaigns 1–3
Publisher: American Astronomical Society
Date: 24-01-2018
Astrophotonic spectroscopy: defining the potential advantage
Publisher: Oxford University Press (OUP)
Date: 03-2010
Galaxy And Mass Assembly (GAMA): deconstructing bimodality – I. Red ones and blue ones
Publisher: Oxford University Press (OUP)
Date: 26-11-2014
The 2dF-SDSS LRG and QSO (2SLAQ) Luminous Red Galaxy Survey
Publisher: Oxford University Press (OUP)
Date: 11-10-2006
Add–drop filter with complex waveguide Bragg grating and multimode interferometer operating on arbitrarily spaced channels
Publisher: The Optical Society
Date: 12-12-2018
DOI: 10.1364/OL.43.006045
Galaxy And Mass Assembly (GAMA): galaxy radial alignments in GAMA groups
Publisher: Oxford University Press (OUP)
Date: 02-07-2013
DOI: 10.1093/MNRAS/STT855
The LEGA-C and SAMI galaxy surveys: quiescent stellar populations and the mass–size plane across 6 Gyr
Publisher: Oxford University Press (OUP)
Date: 16-03-2022
Abstract: We investigate changes in stellar population age and metallicity ([Z/H]) scaling relations for quiescent galaxies from intermediate redshift (0.60 ≤ $z$ ≤ 0.76) using the LEGA-C Survey to low redshift (0.014 ≤ $z$ ≤ 0.10) using the SAMI Galaxy Survey. Specifically, we study how the spatially integrated global age and metallicity of in idual quiescent galaxies vary in the mass–size plane, using the stellar mass M* and a dynamical mass proxy derived from the virial theorem MD ∝ σ2 Re. We find that, similarly to at low redshift, the metallicity of quiescent galaxies at 0.60 ≤ $z$ ≤ 0.76 closely correlates with M/Re (a proxy for the gravitational potential or escape velocity), in that galaxies with deeper potential wells are more metal-rich. This supports the hypothesis that the relation arises due to the gravitational potential regulating the retention of metals by determining the escape velocity for metal-rich stellar and supernova ejecta to escape the system and avoid being recycled into later stellar generations. Conversely, we find no correlation between age and surface density ($M/R_\\mathrm{e}^2$) at 0.60 ≤ $z$ ≤ 0.76, despite this relation being strong at low redshift. We consider this change in the age–$M/R_\\mathrm{e}^2$ relation in the context of the redshift evolution of the star-forming and quiescent mass–size relations, and find our results are consistent with galaxies forming more compactly at higher redshifts and remaining compact throughout their evolution. Furthermore, galaxies appear to quench at a characteristic surface density that decreases with decreasing redshift. The $z$ ∼ 0 age–$M/R_\\mathrm{e}^2$ relation is therefore a result of building up the quiescent and star-forming populations with galaxies that formed at a range of redshifts and therefore a range of surface densities.
Correlations between age, kinematics, and chemistry as seen by the RAVE survey
Publisher: Oxford University Press (OUP)
Date: 24-04-2018
Towards a multi-input astrophotonic AWG spectrograph
Publisher: SPIE
Date: 10-07-2018
DOI: 10.1117/12.2312789
Hector: A new massively multiplexed IFU instrument for the Anglo-Australian Telescope
Publisher: SPIE
Date: 04-08-2016
DOI: 10.1117/12.2230740
PIMMS échelle: the next generation of compact diffraction limited spectrographs for arbitrary input beams
Publisher: SPIE
Date: 08-07-2014
DOI: 10.1117/12.2055638
Divide and conquer: an efficient solution to highly multimoded photonic lanterns from multicore fibres
Publisher: The Optical Society
Date: 13-07-2017
DOI: 10.1364/OE.25.017530
The Baryon Halo of the Milky Way: A Fossil Record of Its Formation
Publisher: American Association for the Advancement of Science (AAAS)
Date: 07-01-2000
DOI: 10.1126/SCIENCE.287.5450.79
Abstract: Astronomers believe that the baryon (stellar) halo of the Milky Way retains a fossil imprint of how it was formed. But a vast literature shows that the struggle to interpret the observations within a consistent framework continues. The evidence indicates that the halo has built up through a process of accretion and merging over billions of years, which is still going on at a low level. Future satellite missions to derive three-dimensional space motions and heavy element (metal) abundances for a billion stars will disentangle the existing web and elucidate how galaxies like our own came into existence.
The GALAH survey: chemical tagging of star clusters and new members in the Pleiades
Publisher: Oxford University Press (OUP)
Date: 17-10-2017
Galaxy evolution in the metric of the cosmic web
Publisher: Oxford University Press (OUP)
Date: 10-10-2017
Multimode fiber devices with single-mode performance
Publisher: Optica Publishing Group
Date: 10-2005
DOI: 10.1364/OL.30.002545
Abstract: A taper transition can couple light between a multimode fiber and several single-mode fibers. If the number of single-mode fibers matches the number of spatial modes in the multimode fiber, the transition can have low loss in both directions. This enables the high performance of single-mode fiber devices to be attained in multimode fibers. We report an experimental proof of concept by using photonic crystal fiber techniques to make the transitions, demonstrating a multimode fiber filter with the transmission spectrum of a single-mode fiber grating.
The SAMI Galaxy Survey: gas content and interaction as the drivers of kinematic asymmetry
Publisher: Oxford University Press (OUP)
Date: 02-2018
DOI: 10.1093/MNRAS/STY273
Exploring the morphology of rave stellar spectra
Publisher: American Astronomical Society
Date: 18-05-2012
Galaxy and Mass Assembly (GAMA): the stellar mass budget of galaxy spheroids and discs
Publisher: Oxford University Press (OUP)
Date: 30-07-2016
On the performance of ELT instrumentation
Publisher: SPIE
Date: 14-06-2006
DOI: 10.1117/12.671619
The SAMI galaxy survey: Satellite galaxies undergo little structural change during their quenching phase
Publisher: Oxford University Press (OUP)
Date: 19-02-2019
DOI: 10.1093/MNRAS/STZ485
Metal-poor lithium-rich giants in the radial velocity experiment survey
Publisher: American Astronomical Society
Date: 29-11-2011
Concepts for multi-IFU robotic positioning systems
Publisher: SPIE
Date: 13-09-2012
DOI: 10.1117/12.925100
On the origin of the angular momentum properties of gas and dark matter in galactic halos and its implications
Publisher: American Astronomical Society
Date: 20-04-2012
The GALAH survey: observational overview andGaiaDR1 companion
Publisher: Oxford University Press (OUP)
Date: 03-11-2016
The GALAH survey: unresolved triple Sun-like stars discovered by the Gaia mission
Publisher: Oxford University Press (OUP)
Date: 21-05-2019
Abstract: The latest Gaia data release enables us to accurately identify stars that are more luminous than would be expected on the basis of their spectral type and distance. During an investigation of the 329 best solar twin candidates uncovered among the spectra acquired by the GALAH survey, we identified 64 such overluminous stars. In order to investigate their exact composition, we developed a data-driven methodology that can generate a synthetic photometric signature and spectrum of a single star. By combining multiple such synthetic stars into an unresolved binary or triple system and comparing the results to the actual photometric and spectroscopic observations, we uncovered 6 definitive triple stellar system candidates and an additional 14 potential candidates whose combined spectrum mimics the solar spectrum. Considering the volume correction factor for a magnitude-limited survey, the fraction of probable unresolved triple stars with long orbital periods is ∼2 per cent. Possible orbital configurations of the candidates were investigated using the selection and observational limits. To validate the discovered multiplicity fraction, the same procedure was used to evaluate the multiplicity fraction of other stellar types.
STAR FORMATION IN ULTRA-FAINT DWARFS: CONTINUOUS OR SINGLE-AGE BURSTS?
Publisher: American Astronomical Society
Date: 27-01-2015
Estimation of the tilt of the stellar velocity ellipsoid from RAVE and implications for mass models
Publisher: Oxford University Press (OUP)
Date: 12-2008
Evolution in the orbital structure of quiescent galaxies from MAGPI, LEGA-C, and SAMI surveys: direct evidence for merger-driven growth over the last 7 Gyr
Publisher: Oxford University Press (OUP)
Date: 21-08-2023
Core-to-core uniformity improvement in multi-core fiber Bragg gratings
Publisher: SPIE
Date: 07-08-2014
DOI: 10.1117/12.2055623
KROSS–SAMI: a direct IFS comparison of the Tully–Fisher relation across 8 Gyr sincez ≈ 1
Publisher: Oxford University Press (OUP)
Date: 17-10-2018
Galaxy And Mass Assembly (GAMA): The group H i mass as a function of halo mass
Publisher: Oxford University Press (OUP)
Date: 26-05-2023
Abstract: We determine the atomic hydrogen (H i) to halo mass relation (HIHM) using Arecibo Legacy Fast ALFA survey H i data at the location of optically selected groups from the Galaxy And Mass Assembly (GAMA) survey. We make direct H i detections for 37 GAMA groups. Using H i group spectral stacking of 345 groups, we study the group H i content as a function of halo mass across a halo mass range of 1011–1014.7 M⊙. We also correct our results for Eddington bias. We find that the group H i mass generally rises as a function of halo mass from 1.3% of the halo mass at $10^{11.6} \\, \\text{M}_\\odot$ to 0.4% at $10^{13.7} \\, \\text{M}_\\odot$ with some indication of flattening towards the high-mass end. Despite the differences in optical survey limits, group catalogues, and halo mass estimation methods, our results are consistent with previous group H i-stacking studies. Our results are also consistent with mock observations from shark and IllustrisTNG.
The GALAH survey: Chemical homogeneity of the Orion complex
Publisher: Oxford University Press (OUP)
Date: 28-06-2021
Abstract: Due to its proximity, the Orion star forming region is often used as a proxy to study processes related to star formation and to observe young stars in the environment they were born in. With the release of Gaia DR2, the distance measurements to the Orion complex are now good enough that the 3D structure of the complex can be explored. Here we test the hypothesis that, due to non-trivial structure and dynamics, and age spread in the Orion complex, the chemical enrichment of youngest stars by early core-collapse supernovae can be observed. We obtained spectra of 794 stars of the Orion complex with the HERMES spectrograph at the Anglo Australian telescope as a part of the GALAH and GALAH-related surveys. We use the spectra of ∼300 stars to derive precise atmospheric parameters and chemical abundances of 25 elements for 15 stellar clusters in the Orion complex. We demonstrate that the Orion complex is chemically homogeneous and that there was no self-pollution of young clusters by core-collapse supernovae from older clusters with a precision of 0.02 dex in relative alpha-elements abundance and 0.06 dex in oxygen abundance we would have been able to detect pollution from a single supernova, given a fortunate location of the SN and favourable conditions for ISM mixing. We estimate that the supernova rate in the Orion complex was very low, possibly producing no supernova by the time the youngest stars of the observed population formed (from around 21 to 8 Myr ago).
The lives of high-redshift mergers
Publisher: Oxford University Press (OUP)
Date: 06-2012
Observational hints of radial migration in disc galaxies from CALIFA
Publisher: EDP Sciences
Date: 26-07-2017
OBSERVATIONAL PROPERTIES OF THE METAL-POOR THICK DISK OF THE MILKY WAY AND INSIGHTS INTO ITS ORIGINS
Publisher: American Astronomical Society
Date: 21-07-2011
GAMA/H-ATLAS: the local dust mass function and cosmic density as a function of galaxy type – a benchmark for models of galaxy evolution
Publisher: Oxford University Press (OUP)
Date: 05-06-2018
Abstract: We present the dust mass function (DMF) of 15 750 galaxies with redshift $z$ & 0.1, drawn from the overlapping area of the GAMA and H-ATLAS surveys. The DMF is derived using the density corrected Vmax method, where we estimate Vmax using: (i) the normal photometric selection limit (pVmax) and (ii) a bivariate brightness distribution (BBD) technique, which accounts for two selection effects. We fit the data with a Schechter function, and find $M^{*}=(4.65 \\pm 0.18)\\times 10^{7}\\,h^2_{70}\\, \\mathrm{ M}_{\\odot }$, α = (−1.22 ± 0.01), $\\phi ^{*}=(6.26 \\pm 0.28)\\times 10^{-3}\\,h^3_{70}\\,\\rm Mpc^{-3}\\,dex^{-1}$. The resulting dust mass density parameter integrated down to 104 M⊙ is Ωd = (1.11 ± 0.02) × 10−6 which implies the mass fraction of baryons in dust is $f_{m_\\mathrm{ b}}=(2.40\\pm 0.04)\\times 10^{-5}$ cosmic variance adds an extra 7–17 per cent uncertainty to the quoted statistical errors. Our measurements have fewer galaxies with high dust mass than predicted by semi-analytic models. This is because the models include too much dust in high stellar mass galaxies. Conversely, our measurements find more galaxies with high dust mass than predicted by hydrodynamical cosmological simulations. This is likely to be from the long time-scales for grain growth assumed in the models. We calculate DMFs split by galaxy type and find dust mass densities of Ωd = (0.88 ± 0.03) × 10−6 and Ωd = (0.060 ± 0.005) × 10−6 for late types and early types, respectively. Comparing to the equivalent galaxy stellar mass functions (GSMF) we find that the DMF for late types is well matched by the GSMF scaled by (8.07 ± 0.35) × 10−4.
Astrophotonics: the application of photonic technology to astronomy
Publisher: SPIE
Date: 17-05-2017
DOI: 10.1117/12.2265958
Chemical separation of disc components using RAVE
Publisher: Oxford University Press (OUP)
Date: 07-07-2016
RAVE spectroscopy of luminous blue variables in the Large Magellanic Cloud
Publisher: EDP Sciences
Date: 22-06-2009
On the origin of core-to-core variations in multi-core fibre Bragg gratings
Publisher: SPIE
Date: 10-07-2018
DOI: 10.1117/12.2312895
The SAMI Galaxy Survey: disc–halo interactions in radio-selected star-forming galaxies
Publisher: Oxford University Press (OUP)
Date: 06-07-2017
The SAMI Galaxy Survey: Asymmetry in gas kinematics and its links to stellar mass and star formation
Publisher: Oxford University Press (OUP)
Date: 12-10-2017
SAMI - A new multi-object IFS for the Anglo-Australian telescope
Publisher: SPIE
Date: 24-09-2012
DOI: 10.1117/12.925115
Complex Waveguide Bragg Gratings For arbitrary spectral filtering
Publisher: IEEE
Date: 07-2016
ARGOS – III. Stellar populations in the Galactic bulge of the Milky Way
Publisher: Oxford University Press (OUP)
Date: 31-01-2013
DOI: 10.1093/MNRAS/STS629
THE RADIAL VELOCITY EXPERIMENT (RAVE): THIRD DATA RELEASE
Publisher: American Astronomical Society
Date: 06-05-2011
Sagittarius dwarf galaxy: Where did all the gas go?
Publisher: Oxford University Press (OUP)
Date: 28-06-2018
Towards a spectroscopic survey of one hundred thousand spatially resolved galaxies with Hector
Publisher: SPIE
Date: 24-07-2014
DOI: 10.1117/12.2055734
The disruption of the Magellanic Stream
Publisher: Cambridge University Press (CUP)
Date: 07-2008
DOI: 10.1017/S1743921308028342
Abstract: We present evidence that the accretion of warm gas onto the Galaxy today is at least as important as cold gas accretion. For more than a decade, the source of the bright Hα emission (up to 750 mR†) along the Magellanic Stream has remained a mystery. We present a hydrodynamical model that explains the known properties of the Hα emission and provides new insights on the lifetime of the Stream clouds. The upstream clouds are gradually disrupted due to their interaction with the hot halo gas. The clouds that follow plough into gas ablated from the upstream clouds, leading to shock ionisation at the leading edges of the downstream clouds. Since the following clouds also experience ablation, and weaker Hα (100–200 mR) is quite extensive, a disruptive cascade must be operating along much of the Stream. In order to light up much of the Stream as observed, it must have a small angle of attack (≈ 20°) to the halo, and this may already find support in new H i observations. Another prediction is that the Balmer ratio (Hα/Hβ) will be substantially enhanced due to the slow shock this will soon be tested by upcoming WHAM observations in Chile. We find that the clouds are evolving on timescales of 100–200 Myr, such that the Stream must be replenished by the Magellanic Clouds at a fairly constant rate (≳ 0.1 M ⊙ yr −1 ). The ablated material falls onto the Galaxy as a warm drizzle diffuse ionized gas at 10 4 K is an important constituent of galactic accretion. The observed Hα emission provides a new constraint on the rate of disruption of the Stream and, consequently, the infall rate of metal-poor gas onto the Galaxy. When the ionized component of the infalling gas is accounted for, the rate of gas accretion is ≳ 0.4 M ⊙ yr −1 , roughly twice the rate deduced from H i observations alone.
Miniature astronomical spectrographs using arrayed-waveguide gratings: capabilities and limitations
Publisher: SPIE
Date: 16-07-2010
DOI: 10.1117/12.856786
Arm and interarm abundance gradients in CALIFA spiral galaxies
Publisher: EDP Sciences
Date: 07-2017
Fibre bragg gratings for temporal spectral astronomy
Publisher: SPIE
Date: 16-07-2010
DOI: 10.1117/12.856784
THE COS/UVES ABSORPTION SURVEY OF THE MAGELLANIC STREAM. III. IONIZATION, TOTAL MASS, AND INFLOW RATE ONTO THE MILKY WAY
Publisher: American Astronomical Society
Date: 13-05-2014
Miniature spectrographs: characterization of arrayed waveguide gratings for astronomy
Publisher: SPIE
Date: 16-07-2010
DOI: 10.1117/12.856782
Diffuse interstellar bands in RAVE survey spectra
Publisher: EDP Sciences
Date: 17-07-2008
The SAMI galaxy survey: exploring the gas-phase mass–metallicity relation
Publisher: Oxford University Press (OUP)
Date: 07-01-2019
DOI: 10.1093/MNRAS/STZ019
Surface brightness fluctuations in NGC 5128 from wide-field photographic plates
Publisher: American Astronomical Society
Date: 10-1993
DOI: 10.1086/116731
Thin disk kinematics from RAVE and the solar motion
Publisher: EDP Sciences
Date: 31-10-2012
The K2 Galactic Archaeology Program: Overview, target selection, and survey properties
Publisher: Oxford University Press (OUP)
Date: 22-07-2022
Abstract: K2 was a community-driven NASA mission where all targets were proposed through guest observer programmes. Here we provide an overview of one of the largest of these endeavours, the K2 Galactic Archaeology Programme (K2GAP), with about 25 per cent of the observed targets being allocated to this programme. K2GAP provides asteroseismic parameters for about 23 000 giant stars across the Galaxy, which together with spectroscopic stellar parameters can give age and masses of stars. We discuss in detail the target selection procedure and provide a python program that implements the selection function (anjibs/k2gap). Broadly speaking, the targets were selected on 2MASS colour J − Ks & 0.5, with finely tuned adjustments for each c aign. We discuss the detection completeness of the asteroseismic parameters νmax and Δν. About 14 per cent of giants were found to miss νmax detections and it was difficult to detect Δν for RC stars. Making use of the selection function, we compare the observed distribution of asteroseismic masses to theoretical predictions. The median asteroseismic mass is higher by about 4 per cent compared to predictions. We provide a selection-function-matched mock catalogue of stars based on a synthetic model of the Galaxy for the community to use in subsequent analyses of the K2GAP data set (physics.usyd.edu.au/k2gap/download/).
Galaxy And Mass Assembly (GAMA): refining the local galaxy merger rate using morphological information
Publisher: Oxford University Press (OUP)
Date: 07-10-2014
Hα emission from high-velocity clouds and their distances
Publisher: American Astronomical Society
Date: 10-11-2003
DOI: 10.1086/378555
Optical-mechanical operation of the F2T2 Filter: A tunable filter designed to search for First Light
Publisher: SPIE
Date: 12-07-2008
DOI: 10.1117/12.789692
AN UPPER LIMIT TO THE DRY MERGER RATE AT ⟨z⟩ ∼ 0.55
Publisher: American Astronomical Society
Date: 14-01-2010
Astrophotonics: molding the flow of light in astronomical instruments [Invited]
Publisher: The Optical Society
Date: 23-06-2017
DOI: 10.1364/OE.25.015549
Developing arrayed waveguide grating spectrographs for multi-object astronomical spectroscopy
Publisher: The Optical Society
Date: 17-01-2012
DOI: 10.1364/OE.20.002062
The SAMI Galaxy Survey: decomposed stellar kinematics of galaxy bulges and disks
Publisher: Oxford University Press (OUP)
Date: 14-05-2020
Abstract: We investigate the stellar kinematics of the bulge and disk components in 826 galaxies with a wide range of morphology from the Sydney-AAO Multi-object Integral-field spectroscopy Galaxy Survey. The spatially resolved rotation velocity (V) and velocity dispersion (σ) of bulge and disk components have been simultaneously estimated using the penalized pixel fitting (ppxf) method with photometrically defined weights for the two components. We introduce a new subroutine of ppxf for dealing with degeneracy in the solutions. We show that the V and σ distributions in each galaxy can be reconstructed using the kinematics and weights of the bulge and disk components. The combination of two distinct components provides a consistent description of the major kinematic features of galaxies over a wide range of morphological types. We present Tully–Fisher and Faber–Jackson relations showing that the galaxy stellar mass scales with both V and σ for both components of all galaxy types. We find a tight Faber–Jackson relation even for the disk component. We show that the bulge and disk components are kinematically distinct: (1) the two components show scaling relations with similar slopes, but different intercepts (2) the spin parameter λR indicates bulges are pressure-dominated systems and disks are supported by rotation and (3) the bulge and disk components have, respectively, low and high values in intrinsic ellipticity. Our findings suggest that the relative contributions of the two components explain, at least to first order, the complex kinematic behaviour of galaxies.
Ionization Cone in the X-Ray Binary LMC X-1
Publisher: American Astronomical Society
Date: 03-10-2008
DOI: 10.1086/593169
Square-core bundles for astronomical imaging
Publisher: SPIE
Date: 24-09-2012
DOI: 10.1117/12.925127
Geometric requirements for photonic lanterns in space division multiplexing
Publisher: The Optical Society
Date: 16-11-2012
DOI: 10.1364/OE.20.027123
Thick disk kinematics from RAVE and the solar motion
Publisher: EDP Sciences
Date: 11-2012
High-resolution elemental abundance analysis of the Hyades supercluster★
Publisher: Oxford University Press (OUP)
Date: 30-05-2011
Centrally concentrated molecular gas driving galactic-scale ionized gas outflows in star-forming galaxies
Publisher: Oxford University Press (OUP)
Date: 25-11-2020
Abstract: We perform a joint analysis of high spatial resolution molecular gas and star-formation rate (SFR) maps in main-sequence star-forming galaxies experiencing galactic-scale outflows of ionized gas. Our aim is to understand the mechanism that determines which galaxies are able to launch these intense winds. We observed CO(1→0) at 1-arcsec resolution with ALMA in 16 edge-on galaxies, which also have 2-arcsec spatial-resolution optical integral field observations from the SAMI Galaxy Survey. Half the galaxies in the s le were previously identified as harbouring intense and large-scale outflows of ionized gas (‘outflow types’) and the rest serve as control galaxies. The data set is complemented by integrated CO(1→0) observations from the IRAM 30-m telescope to probe the total molecular gas reservoirs. We find that the galaxies powering outflows do not possess significantly different global gas fractions or star-formation efficiencies when compared with a control s le. However, the ALMA maps reveal that the molecular gas in the outflow-type galaxies is distributed more centrally than in the control galaxies. For our outflow-type objects, molecular gas and star-formation are largely confined within their inner effective radius (reff), whereas in the control s le, the distribution is more diffuse, extending far beyond reff. We infer that outflows in normal star-forming galaxies may be caused by dynamical mechanisms that drive molecular gas into their central regions, which can result in locally enhanced gas surface density and star-formation.
The SAMI Galaxy Survey: stellar population and structural trends across the Fundamental Plane
Publisher: Oxford University Press (OUP)
Date: 23-04-2021
Abstract: We study the Fundamental Plane (FP) for a volume- and luminosity-limited s le of 560 early-type galaxies from the SAMI survey. Using r-band sizes and luminosities from new multi-Gaussian expansion photometric measurements, and treating luminosity as the dependent variable, the FP has coefficients a = 1.294 ± 0.039, b = 0.912 ± 0.025, and zero-point c = 7.067 ± 0.078. We leverage the high signal-to-noise ratio of SAMI integral field spectroscopy, to determine how structural and stellar population observables affect the scatter about the FP. The FP residuals correlate most strongly (8σ significance) with luminosity-weighted simple stellar population (SSP) age. In contrast, the structural observables surface mass density, rotation-to-dispersion ratio, Sérsic index, and projected shape all show little or no significant correlation. We connect the FP residuals to the empirical relation between age (or stellar mass-to-light ratio Υ⋆ ) and surface mass density, the best predictor of SSP age amongst parameters based on FP observables. We show that the FP residuals (anti)correlate with the residuals of the relation between surface density and Υ⋆ . This correlation implies that part of the FP scatter is due to the broad age and Υ⋆ distribution at any given surface mass density. Using virial mass and Υ⋆, we construct a simulated FP and compare it to the observed FP. We find that, while the empirical relations between observed stellar population relations and FP observables are responsible for most (75 per cent) of the FP scatter, on their own they do not explain the observed tilt of the FP away from the virial plane.
CHROMOSPHERICALLY ACTIVE STARS IN THE RAVE SURVEY. II. YOUNG DWARFS IN THE SOLAR NEIGHBORHOOD
Publisher: American Astronomical Society
Date: 18-01-2017
Pregalactic metal enrichment: The chemical signatures of the first stars
Publisher: American Physical Society (APS)
Date: 15-05-2013
Key dynamical results from the SAMI Galaxy Survey
Publisher: Cambridge University Press (CUP)
Date: 06-2019
DOI: 10.1017/S174392131900913X
Abstract: We present an overview of recent key results from the SAMI Galaxy Survey on the build-up of mass and angular momentum in galaxies across morphology and environment. The SAMI Galaxy survey is a multi-object integral field spectroscopic survey and provides a wealth of spatially-resolved, two-dimensional stellar and gas measurements for galaxies of all morphological types, with high-precision due the stable spectral resolution of the AAOmega spectrograph. The s le size of ~3000 galaxies allows for iding the s le in bins of stellar mass, environment, and star-formation or morphology, whilst maintaining a statistical significant number of galaxies in each bin. By combining imaging, spatially resolved dynamics, and stellar population measurements, our result demonstrate the power of utilising integral field spectroscopy on a large s le of galaxies to further our understanding of physical processes involved in the build-up of stellar mass and angular momentum in galaxies.
The selection function of the RAVE survey
Publisher: Oxford University Press (OUP)
Date: 17-03-2017
DOI: 10.1093/MNRAS/STX606
The dawning of the stream of Aquarius in RAVE
Publisher: American Astronomical Society
Date: 26-01-2011
Multicore fibre technology: The road to multimode photonics
Publisher: SPIE
Date: 22-07-2016
DOI: 10.1117/12.2231924
The Hector Survey: integral field spectroscopy of 100,000 galaxies
Publisher: Cambridge University Press (CUP)
Date: 07-2014
DOI: 10.1017/S1743921314009247
Abstract: In March 2013, the Sydney–AAO Multi-object Integral field spectrograph (SAMI) began a major survey of 3400 galaxies at the AAT, the largest of its kind to date. At the time of writing, over a third of the targets have been observed and the scientific impact has been immediate. The Manga galaxy survey has now started at the SDSS telescope and will target an even larger s le of nearby galaxies. In Australia, the community is now gearing up to deliver a major new facility called Hector that will allow integral field spectroscopy of 100 galaxies observed simultaneously. By the close of the decade, it will be possible to obtain integral field spectroscopy of 100,000 galaxies over 3000 square degrees of sky down to r =17 (median). Many of these objects will have HI imaging from the new ASKAP radio surveys. We discuss the motivation for such a survey and the use of new cosmological simulations that are properly matched to the integral field observations. The Hector survey will open up a new and unique parameter space for galaxy evolution studies.
Galaxy and Mass Assembly (GAMA)
Publisher: Oxford University Press (OUP)
Date: 14-04-2018
DOI: 10.1093/MNRAS/STY933
Accretion of the Magellanic system onto the galaxy
Publisher: American Astronomical Society
Date: 14-11-2011
The structure and dynamics of the gaseous and stellar components in Centaurus A
Publisher: American Astronomical Society
Date: 03-1992
DOI: 10.1086/171102
The environment and characteristics of low-redshift galaxies detected by the Herschel-ATLAS
Publisher: Oxford University Press (OUP)
Date: 24-10-2011
SPATIALLY RESOLVED STAR FORMATION MAIN SEQUENCE OF GALAXIES IN THE CALIFA SURVEY
Publisher: American Astronomical Society
Date: 18-04-2016
Characterization and on-sky demonstration of an integrated photonic spectrograph for astronomy
Publisher: Optica Publishing Group
Date: 10-2009
DOI: 10.1364/OE.17.018643
Star formation driven galactic winds in UGC 10043
Publisher: Oxford University Press (OUP)
Date: 23-12-2016
The SAMI Galaxy Survey: instrument specification and target selection
Publisher: Oxford University Press (OUP)
Date: 13-01-2015
The search for celestial positronium via the recombination spectrum
Publisher: American Astronomical Society
Date: 23-11-2009
The SAMI Galaxy Survey: Stellar Population Gradients of Central Galaxies
Publisher: American Astronomical Society
Date: 16-06-2020
The SAMI Galaxy Survey: a statistical approach to an optimal classification of stellar kinematics in galaxy surveys
Publisher: Oxford University Press (OUP)
Date: 26-05-2021
Abstract: Large galaxy s les from multiobject integral field spectroscopic (IFS) surveys now allow for a statistical analysis of the z ∼ 0 galaxy population using resolved kinematic measurements. However, the improvement in number statistics comes at a cost, with multiobject IFS survey more severely impacted by the effect of seeing and lower signal-to-noise ratio. We present an analysis of ∼1800 galaxies from the SAMI Galaxy Survey taking into account these effects. We investigate the spread and overlap in the kinematic distributions of the spin parameter proxy $\\lambda _{R_{\\rm {e}}}$ as a function of stellar mass and ellipticity εe. For SAMI data, the distributions of galaxies identified as regular and non-regular rotators with kinemetry show considerable overlap in the $\\lambda _{R_{\\rm {e}}}$–εe diagram. In contrast, visually classified galaxies (obvious and non-obvious rotators) are better separated in $\\lambda _{R_{\\rm {e}}}$ space, with less overlap of both distributions. Then, we use a Bayesian mixture model to analyse the observed $\\lambda _{R_{\\rm {e}}}$–log (M⋆/M⊙) distribution. By allowing the mixture probability to vary as a function of mass, we investigate whether the data are best fit with a single kinematic distribution or with two. Below log (M⋆/M⊙) ∼ 10.5, a single beta distribution is sufficient to fit the complete $\\lambda _{R_{\\rm {e}}}$ distribution, whereas a second beta distribution is required above log (M⋆/M⊙) ∼ 10.5 to account for a population of low-$\\lambda _{R_{\\rm {e}}}$ galaxies. While the Bayesian mixture model presents the cleanest separation of the two kinematic populations, we find the unique information provided by visual classification of galaxy kinematic maps should not be disregarded in future studies. Applied to mock-observations from different cosmological simulations, the mixture model also predicts bimodal $\\lambda _{R_{\\rm {e}}}$ distributions, albeit with different positions of the $\\lambda _{R_{\\rm {e}}}$ peaks. Our analysis validates the conclusions from previous, smaller IFS surveys, but also demonstrates the importance of using selection criteria for identifying different kinematic classes that are dictated by the quality and resolution of the observed or simulated data.
The Photonic TIGER: A multicore fiber-fed spectrograph
Publisher: SPIE
Date: 13-09-2012
DOI: 10.1117/12.925254
A genetic approach to the history of the Magellanic Clouds
Publisher: Oxford University Press (OUP)
Date: 29-08-2014
BASIS: Bayfordbury single-object integral field spectrograph
Publisher: SPIE
Date: 24-09-2012
DOI: 10.1117/12.925378
Chemical Homogeneity in Collinder 261 and Implications for Chemical Tagging
Publisher: American Astronomical Society
Date: 12-02-2007
DOI: 10.1086/511182
Atmospheric OH suppression with GNOSIS at the Anglo-Australian telescope
Publisher: IEEE
Date: 08-2011
Is the sky falling? Searching for stellar streams in the local Milky Way disc in the CORAVEL and RAVE surveys
Publisher: Oxford University Press (OUP)
Date: 02-2008
APASS Landolt-Sloan BVgri photometry of RAVE stars. I. Data, effective temperatures, and reddenings
Publisher: American Astronomical Society
Date: 26-09-2014
Globular cluster and galaxy formation: M31, the Milky Way, and implications for globular cluster systems of spiral galaxies
Publisher: American Astronomical Society
Date: 10-10-2004
DOI: 10.1086/423334
INSIGHTS ON THE STELLAR MASS-METALLICITY RELATION FROM THE CALIFA SURVEY
Publisher: American Astronomical Society
Date: 28-07-2014
Galaxy And Mass Assembly: the G02 field, Herschel–ATLAS target selection and data release 3
Publisher: Oxford University Press (OUP)
Date: 24-11-2017
Kinematics of the Magellanic Stream and Implications for Its Ionization
Publisher: American Astronomical Society
Date: 29-06-2020
WISE × SuperCOSMOS PHOTOMETRIC REDSHIFT CATALOG: 20 MILLION GALAXIES OVER 3 π STERADIANS
Publisher: American Astronomical Society
Date: 13-07-2016
Characterization of Low Loss Waveguides Using Bragg Gratings
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 07-2018
The SAMI Galaxy Survey: the role of disc fading and progenitor bias in kinematic transitions
Publisher: Oxford University Press (OUP)
Date: 26-05-2021
Abstract: We use comparisons between the Sydney-AAO Multi-object Integral Field Spectrograph (SAMI) Galaxy Survey and equilibrium galaxy models to infer the importance of disc fading in the transition of spirals into lenticular (S0) galaxies. The local S0 population has both higher photometric concentration and lower stellar spin than spiral galaxies of comparable mass and we test whether this separation can be accounted for by passive aging alone. We construct a suite of dynamically self-consistent galaxy models, with a bulge, disc, and halo using the galactics code. The dispersion-dominated bulge is given a uniformly old stellar population, while the disc is given a current star formation rate putting it on the main sequence, followed by sudden instantaneous quenching. We then generate mock observables (r-band images, stellar velocity, and dispersion maps) as a function of time since quenching for a range of bulge/total (B/T) mass ratios. The disc fading leads to a decline in measured spin as the bulge contribution becomes more dominant, and also leads to increased concentration. However, the quantitative changes observed after 5 Gyr of disc fading cannot account for all of the observed difference. We see similar results if we instead sub ide our SAMI Galaxy Survey s le by star formation (relative to the main sequence). We use EAGLE simulations to also take into account progenitor bias, using size evolution to infer quenching time. The EAGLE simulations suggest that the progenitors of current passive galaxies typically have slightly higher spin than present day star-forming disc galaxies of the same mass. As a result, progenitor bias moves the data further from the disc fading model scenario, implying that intrinsic dynamical evolution must be important in the transition from star-forming discs to passive discs.
Ionizing Photons and Extreme-Ultraviolet Excesses in Clusters of Galaxies
Publisher: American Astronomical Society
Date: 06-2001
DOI: 10.1086/320694
SINGLE-LINED SPECTROSCOPIC BINARY STAR CANDIDATES IN THE RAVE SURVEY
Publisher: American Astronomical Society
Date: 11-05-2011
Photonic lanterns
Publisher: Walter de Gruyter GmbH
Date: 16-12-2013
Abstract: Multimode optical fibers have been primarily (and almost solely) used as “light pipes” in short distance telecommunications and in remote and astronomical spectroscopy. The modal properties of the multimode waveguides are rarely exploited and mostly discussed in the context of guiding light. Until recently, most photonic applications in the applied sciences have arisen from developments in telecommunications. However, the photonic lantern is one of several devices that arose to solve problems in astrophotonics and space photonics. Interestingly, these devices are now being explored for use in telecommunications and are likely to find commercial use in the next few years, particularly in the development of compact spectrographs. Photonic lanterns allow for a low-loss transformation of a multimode waveguide into a discrete number of single-mode waveguides and vice versa, thus enabling the use of single-mode photonic technologies in multimode systems. In this review, we will discuss the theory and function of the photonic lantern, along with several different variants of the technology. We will also discuss some of its applications in more detail. Furthermore, we foreshadow future applications of this technology to the field of nanophotonics.
The metal-enriched outer disk of NGC2915
Publisher: American Astronomical Society
Date: 30-04-2010
Tunable filter imaging of high-redshift quasar fields
Publisher: Oxford University Press (OUP)
Date: 24-04-2012
Imaging fabry-perot spectroscopy of NGC 5775: Kinematics of the diffuse ionized gas halo
Publisher: American Astronomical Society
Date: 2006
DOI: 10.1086/497902
New age fibers: the children of the photonic revolution
Publisher: SPIE
Date: 24-09-2004
DOI: 10.1117/12.550991
Principal component analysis on chemical abundances spaces
Publisher: Oxford University Press (OUP)
Date: 13-02-2012
Galaxy And Mass Assembly (GAMA): colour- and luminosity-dependent clustering from calibrated photometric redshifts
Publisher: Oxford University Press (OUP)
Date: 03-08-2012
Galaxy and Mass Assembly (GAMA): ugriz galaxy luminosity functions
Publisher: Oxford University Press (OUP)
Date: 12-12-2011
On the origin of the Z-shaped narrow-line region in the Seyfert galaxy NGC 3516
Publisher: American Astronomical Society
Date: 04-1993
DOI: 10.1086/116512
Hector: A high-multiplex survey instrument for spatially-resolved galaxy spectroscopy
Publisher: SPIE
Date: 24-09-2012
DOI: 10.1117/12.925260
Galaxy and Mass Assembly (GAMA): merging galaxies and their properties
Publisher: Oxford University Press (OUP)
Date: 10-09-2014
Astrophotonics: The Rise of Integrated Photonics in Astronomy
Publisher: The Optical Society
Date: 05-2019
The rave catalog of stellar elemental abundances: First data release
Publisher: American Astronomical Society
Date: 11-11-2011
Classical Spectroscopy
Publisher: Elsevier
Date: 1996
Clues to galaxy formation
Publisher: Springer Science and Business Media LLC
Date: 15-07-1999
DOI: 10.1038/22230
The wobbly Galaxy: Kinematics north and south with RAVE red-clump giants
Publisher: Oxford University Press (OUP)
Date: 03-10-2013
Galactic seismology: the evolving ‘phase spiral’ after the Sagittarius dwarf impact
Publisher: Oxford University Press (OUP)
Date: 11-03-2021
Abstract: In 2018, the ESA Gaia satellite discovered a remarkable spiral pattern (‘phase spiral’) in the z − Vz phase plane throughout the solar neighbourhood, where z and Vz are the displacement and velocity of a star perpendicular to the Galactic disc. In response to Binney & Schönrich’s analytic model of a disc-crossing satellite to explain the Gaia data, we carry out a high-resolution, N-body simulation (N ≈ 108 particles) of an impulsive mass (2 × 1010 M⊙) that interacts with a cold stellar disc at a single transit point. The disc response is complex since the impulse triggers a superposition of two distinct bisymmetric (m = 2) modes − a density wave and a corrugated bending wave − that wrap up at different rates. Stars in the faster density wave wrap up with time T according to ϕD(R, T) = (ΩD(R) + Ωo) T, where ϕD describes the spiral pattern and ΩD = Ω(R) − κ(R)/2, where κ is the epicyclic frequency. While the pattern speed Ωo is small, it is non-zero. The slower bending wave wraps up according to ΩB ≈ ΩD/2 producing a corrugated wave. The bunching effect of the density wave triggers the phase spiral as it rolls up and down on the corrugated wave (‘roller coaster’ model). The phase spiral emerges slowly about ΔT ≈ 400 Myr after impact. It appears to be a long-lived, disc-wide phenomenon that continues to evolve over most of the 2 Gyr simulation. Thus, given Sagittarius’ (Sgr) low total mass today (Mtot ∼ 3 × 108 M⊙ within 10 kpc diameter), we believe that the phase spiral was excited by the disc-crossing dwarf some 1–2 Gyr before the recent transit. For this to be true, Sgr must be losing mass at 0.5–1 dex per orbit loop.
Erratum “Milky Way Tomography with the SkyMapper Southern Survey. II. Photometric Recalibration of SMSS DR2” (2021, ApJ, 907, 68)
Publisher: American Astronomical Society
Date: 2022
The GALAH Survey: dependence of elemental abundances on age and metallicity for stars in the Galactic disc
Publisher: Oxford University Press (OUP)
Date: 25-11-2021
Abstract: Using data from the GALAH survey, we explore the dependence of elemental abundances on stellar age and metallicity among Galactic disc stars. We find that the abundance of most elements can be predicted from age and [Fe/H] with an intrinsic scatter of about 0.03 dex. We discuss the possible causes for the existence of the abundance–age–metallicity relations. Using a stochastic chemical enrichment scheme that takes the volume of supernovae remnants into account, we show the intrinsic scatter is expected to be small, about 0.05 dex or even smaller if there is additional mixing in the ISM. Elemental abundances show trends with both age and metallicity and the relationship is well described by a simple model in which the dependence of abundance ([X/Fe]) on age and [Fe/H] are additively separable. Elements can be grouped based on the direction of their abundance gradient in the (age,[Fe/H]) plane and different groups can be roughly associated with three distinct nucleosynthetic production sites, the exploding massive stars, the exploding white dwarfs, and the AGB stars. However, the abundances of some elements, like Co, La, and Li, show large scatter for a given age and metallicity, suggesting processes other than simple Galactic chemical evolution are at play. We also compare the abundance trends of main-sequence turn-off (MSTO) stars against that of giants, whose ages were estimated using asteroseismic information from the K2 mission. For most elements, the trends of MSTO stars are similar to that of giants. The existence of abundance relations implies that we can estimate the age and birth radius of disc stars, which is important for studying the dynamic and chemical evolution of the Galaxy.
The GALAH survey: accreted stars also inhabit the Spite plateau
Publisher: Oxford University Press (OUP)
Date: 15-07-2021
Abstract: The European Space Agency (ESA) Gaia mission has enabled the remarkable discovery that a large fraction of the stars near the solar neighbourhood are debris from a single in-falling system, the so-called Gaia-Sausage-Enceladus (GSE). This discovery provides astronomers for the first time with a large cohort of easily observable, unevolved stars that formed in a single extragalactic environment. Here we use these stars to investigate the ‘Spite plateau’ – the near-constant lithium abundance observed in unevolved metal-poor stars across a wide range of metallicities (−3 & [Fe/H] & −1). Our aim is to test whether in idual galaxies could have different Spite plateaus – e.g. the interstellar medium could be more depleted in lithium in a lower galactic mass system due to it having a smaller reservoir of gas. We identified 93 GSE dwarf stars observed and analysed by the GALactic Archaeology with HERMES (GALAH) survey as part of its Data Release 3 (DR3). Orbital actions were used to select s les of GSE stars, and comparison s les of halo and disc stars. We find that the GSE stars show the same lithium abundance as other likely accreted stars and in situ Milky Way stars. Formation environment leaves no imprint on lithium abundances. This result fits within the growing consensus that the Spite plateau, and more generally the ‘cosmological lithium problem’ – the observed discrepancy between the amount of lithium in warm, metal-poor dwarf stars in our Galaxy, and the amount of lithium predicted to have been produced by big bang nucleosynthesis – is the result of lithium depletion processes within stars.
THE SAMI GALAXY SURVEY
Publisher: American Astronomical Society
Date: 17-11-2016
The GALAH survey: co-orbiting stars and chemical tagging
Publisher: Oxford University Press (OUP)
Date: 10-11-2018
Beyond BPT: A New Multidimensional Diagnostic Diagram for Classifying Power Sources Tested Using the SAMI Galaxy Survey
Publisher: American Astronomical Society
Date: 25-08-2023
Abstract: Current methods of identifying the ionizing source of nebular emission in galaxies are well defined for the era of single-fiber spectroscopy, but still struggle to differentiate the complex and overlapping ionization sources in some galaxies. With the advent of integral field spectroscopy, the limits of these previous classification schemes are more apparent. We propose a new method for distinguishing the ionizing source in resolved galaxy spectra by use of a multidimensional diagnostic diagram that compares emission-line ratios with velocity dispersion on a spaxel-by-spaxel basis within a galaxy. This new method is tested using the Sydney-Australian-Astronomical-Observatory Multi-object Integral-Field Spectrograph Galaxy Survey (SAMI) Data Release 3 (DR3), which contains 3068 galaxies at z 0.12. Our results are released as ionization maps available alongside the SAMI DR3 public data. Our method accounts for a more erse range of ionization sources than the standard suite of emission-line diagnostics we find 1433 galaxies with a significant contribution from non-star-forming ionization using our improved method as compared to 316 galaxies identified using only emission-line ratio diagnostics. Within these galaxies, we further identify 886 galaxies hosting unique signatures inconsistent with standard ionization by H ii regions, active galactic nuclei, or shocks. These galaxies span a wide range of masses and morphological types and comprise a sizable portion of the galaxies used in our s le. With our revised method, we show that emission-line diagnostics alone do not adequately differentiate the multiple ways to ionize gas within a galaxy.
Discovery of a 500 Parsec Shell in the Nucleus of Centaurus A
Publisher: American Astronomical Society
Date: 17-03-2006
DOI: 10.1086/503670
Chemical enrichment and radial migration in the Galactic disc – the origin of the [αFe] double sequence
Publisher: Oxford University Press (OUP)
Date: 26-07-2021
Abstract: The ([α/Fe], [Fe/H]) distribution of Milky Way stars shows at least two distinct sequences, which have traditionally been associated with the thin and thick disc components. The abundance distribution varies systematically with location R and |z| across the Galaxy. We reproduce this using an analytical chemodynamical model that includes the effects of radial migration and kinematic heating. Unlike some earlier models, our scheme does not require a distinct thick disc component emerging from a separate evolutionary path. The proposed model has a continuous star formation history and a continuous age velocity dispersion relation. Moreover, [α/Fe] is constant for stellar ages less than 8 Gyr, but increases sharply for older stars over a time-scale of 1.5 Gyr. The gap between the two sequences is due to this sharp transition. We show that the high-[α/Fe] sequence at the low-metallicity end is simply a pile-up of old stars, but towards the high-metallicity end, the age progressively decreases and stars have small birth radii. Our model successfully explains the uniformity of the locus of the high-[α/Fe] sequence across different locations. The low-[α/Fe] sequence contains stars with different birth radii that owes its existence to radial migration. For the low-[α/Fe] stars, angular momentum is anticorrelated with [Fe/H], while the opposite is true for high-[α/Fe] stars. We show that the later trend can be explained by the increase of circular velocity with time. If radial migration is not included, the model fails to generate the double sequence and instead shows only a single sequence. Our simple scheme has major advantages over earlier chemodynamical models, as we show.
Spitzer Space Telescope Infrared Spectrograph mapping of the central kpc of Centaurus A
Publisher: Oxford University Press (OUP)
Date: 03-2008
Crepuscular Rays from the Highly Inclined Active Galactic Nucleus in IC 5063*
Publisher: American Astronomical Society
Date: 10-2020
Abstract: On Earth near sunset, the Sun may cast “crepuscular rays” such that clouds near the horizon obscure the origin of light scattered in bright rays. In principle, active galactic nuclei (AGN) should be able to produce similar effects. Using new Hubble Space Telescope (HST) near-infrared and optical observations, we show that the active galaxy IC 5063 contains broad radial rays extending to ≳11 kpc from the nucleus. We argue that the bright rays may arise from dusty scattering of continuum emission from the active nucleus, while the dark rays are due to shadowing near the nucleus, possibly by a warped torus. We also consider alternative AGN-related and stellar origins for the extended light.
Galaxy and Mass Assembly: FUV, NUV, ugrizYJHK Petrosian, Kron and Sérsic photometry
Publisher: Oxford University Press (OUP)
Date: 12-2010
GNOSIS: A novel near-infrared OH suppression unit at the AAT
Publisher: SPIE
Date: 24-09-2012
DOI: 10.1117/12.926483
GNOSIS: An OH suppression unit for near-infrared spectrographs
Publisher: SPIE
Date: 16-07-2010
DOI: 10.1117/12.856348
PIMMS: Photonic integrated multimode microspectrograph
Publisher: SPIE
Date: 16-07-2010
DOI: 10.1117/12.856347
The KMOS Redshift One Spectroscopic Survey (KROSS): The origin of disc turbulence in z≈1 star-forming galaxies
Publisher: Oxford University Press (OUP)
Date: 23-11-2018
The SAMI Galaxy Survey: Data Release One with emission-line physics value-added products
Publisher: Oxford University Press (OUP)
Date: 11-12-2017
The SAMI Galaxy Survey: global stellar populations on the size–mass plane
Publisher: Oxford University Press (OUP)
Date: 24-08-2017
Distance determination for RAVE stars using stellar models
Publisher: EDP Sciences
Date: 02-2010
The SAMI galaxy survey: Can we trust aperture corrections to predict star formation?
Publisher: Oxford University Press (OUP)
Date: 25-11-2016
The SAMI Galaxy Survey: Unveiling the nature of kinematically offset active galactic nuclei
Publisher: Oxford University Press (OUP)
Date: 16-06-2015
New distances to RAVE stars
Publisher: Oxford University Press (OUP)
Date: 05-11-2014
Galaxy And Mass Assembly (GAMA): the connection between metals, specific SFR and H i gas in galaxies: the Z–SSFR relation
Publisher: Oxford University Press (OUP)
Date: 11-05-2013
Galaxy And Mass Assembly (GAMA): the effect of close interactions on star formation in galaxies
Publisher: Oxford University Press (OUP)
Date: 08-07-2015
Astrophotonic micro-spectrographs in the era of ELTs
Publisher: SPIE
Date: 04-08-2014
DOI: 10.1117/12.2055532
Galaxy And Mass Assembly (GAMA): growing up in a bad neighbourhood – how do low-mass galaxies become passive?
Publisher: Oxford University Press (OUP)
Date: 03-12-2015
Hexabundles: Imaging fiber arrays for low-light astronomical applications
Publisher: The Optical Society
Date: 27-01-2011
DOI: 10.1364/OE.19.002649
The SAMI Pilot Survey: The fundamental and mass planes in three low-redshift clusters
Publisher: Oxford University Press (OUP)
Date: 16-06-2015
The influence of patient insemination on the implantation rate in an in vitro fertilization and embryo transfer program
Publisher: Elsevier BV
Date: 08-1986
DOI: 10.1016/S0015-0282(16)49521-X
Abstract: The implantation rates and subsequent pregnancy rates in in vitro fertilization (IVF) programs are lower than those currently seen in the normal fertile population. During IVF treatment regimens, intercourse is not allowed and artificial insemination is normally excluded. This trial, involving the deposition of semen in the high vaginal area, was undertaken for evaluation of the influence of sperm in the reproductive tract on subsequent implantation rates. The results show that the implantation rate, as assessed by a rise in the human chorionic gonadotropin levels in inseminated patients, was 53%, compared with 23% in the control group. The implantation rate of 54% in the group who had tubal occlusion or no fallopian tubes was not significantly different from the implantation rate of 50% in the group with patent tubes, which suggests that the site of sperm influence was on the endometrium and that the absence of the fallopian tube has no significant effect upon this influence.
Hexabundles: Imaging fibre arrays for low-light astronomical applications
Publisher: SPIE
Date: 16-07-2010
DOI: 10.1117/12.856345
HERMES: Revisions in the design for a high-resolution multi-element spectrograph for the AAT
Publisher: SPIE
Date: 16-07-2010
DOI: 10.1117/12.856103
The GALAH survey: relative throughputs of the 2dF fibre positioner and the HERMES spectrograph from stellar targets
Publisher: Oxford University Press (OUP)
Date: 30-03-2016
DOI: 10.1093/MNRAS/STW746
The stellar-to-halo mass relation of GAMA galaxies from 100 deg2of KiDS weak lensing data
Publisher: Oxford University Press (OUP)
Date: 12-04-2016
DOI: 10.1093/MNRAS/STW747
The role of the halo magnetic field on accretion through high-velocity clouds
Publisher: Oxford University Press (OUP)
Date: 27-11-2021
Abstract: High-velocity clouds (HVCs) are believed to be an important source of gas accretion for star formation in the Milky Way. Earlier numerical studies have found that the Galactic magnetic field and radiative cooling strongly affects accretion. However, these effects have not previously been included together in the context of clouds falling through the Milky Way’s gravitational potential. We explore this by simulating an initially stationary cloud falling through the hot hydrostatic corona towards the disc. This represents an HVC that has condensed out of the corona. We include the magnetic field in the corona to examine its effect on accretion of the HVC and its associated cold gas. Remnants of the original cloud survive in all cases, although a strong magnetic field causes it to split into several fragments. We find that mixing of cold and hot gas leads to cooling of coronal gas and an overall growth with time in cold gas mass, despite the low metallicity of the cloud and corona. The role of the magnetic field is to (moderately to severely) suppress the mixing and subsequent cooling, which in turn leads to less accretion compared to when the field is absent. A stronger field leads to less suppression of condensation because it enhances Rayleigh–Taylor instability. However, magnetic tension in a stronger field substantially decelerates condensed cloudlets. These have velocities typically a factor 3–8 below the velocity of the main cloud remnants by the end of the simulation. Some of these cloudlets likely disperse before reaching the disc.
The chemical signatures of the first star clusters in the universe
Publisher: American Astronomical Society
Date: 30-08-2010
Shocks, illumination cones and intrinsic gas structures in the extreme radio galaxy 3C 265
Publisher: Oxford University Press (OUP)
Date: 04-2002
Imaging spectrophotometry of ionized gas in NGC 1068. III - Anisotropic excitation of the large-scale disk by scattering of nuclear continuum
Publisher: American Astronomical Society
Date: 07-1991
DOI: 10.1086/170219
Detection and measurement from narrow-band tunable filter scans
Publisher: Oxford University Press (OUP)
Date: 02-2002
Galaxy And Mass Assembly (GAMA): Environmental Quenching of Centrals and Satellites in Groups
Publisher: Oxford University Press (OUP)
Date: 09-01-2019
The Sydney-AAO Multi-object Integral field spectrograph
Publisher: Oxford University Press (OUP)
Date: 02-2012
Astrophotonics: the future of astronomical instrumentation
Publisher: OSA
Date: 2015
A well-fed black hole
Publisher: Springer Science and Business Media LLC
Date: 1997
DOI: 10.1038/385022A0
The Taipan Galaxy Survey: Scientific Goals and Observing Strategy
Publisher: Cambridge University Press (CUP)
Date: 2017
DOI: 10.1017/PASA.2017.41
Abstract: The Taipan galaxy survey (hereafter simply ‘Taipan’) is a multi-object spectroscopic survey starting in 2017 that will cover 2π steradians over the southern sky (δ ≲ 10°, | b | ≳ 10°), and obtain optical spectra for about two million galaxies out to z 0.4. Taipan will use the newly refurbished 1.2-m UK Schmidt Telescope at Siding Spring Observatory with the new TAIPAN instrument, which includes an innovative ‘Starbugs’ positioning system capable of rapidly and simultaneously deploying up to 150 spectroscopic fibres (and up to 300 with a proposed upgrade) over the 6° diameter focal plane, and a purpose-built spectrograph operating in the range from 370 to 870 nm with resolving power R ≳ 2000. The main scientific goals of Taipan are (i) to measure the distance scale of the Universe (primarily governed by the local expansion rate, H 0 ) to 1% precision, and the growth rate of structure to 5% (ii) to make the most extensive map yet constructed of the total mass distribution and motions in the local Universe, using peculiar velocities based on improved Fundamental Plane distances, which will enable sensitive tests of gravitational physics and (iii) to deliver a legacy s le of low-redshift galaxies as a unique laboratory for studying galaxy evolution as a function of dark matter halo and stellar mass and environment. The final survey, which will be completed within 5 yrs, will consist of a complete magnitude-limited s le ( i ⩽ 17) of about 1.2 × 10 6 galaxies supplemented by an extension to higher redshifts and fainter magnitudes ( i ⩽ 18.1) of a luminous red galaxy s le of about 0.8 × 10 6 galaxies. Observations and data processing will be carried out remotely and in a fully automated way, using a purpose-built automated ‘virtual observer’ software and an automated data reduction pipeline. The Taipan survey is deliberately designed to maximise its legacy value by complementing and enhancing current and planned surveys of the southern sky at wavelengths from the optical to the radio it will become the primary redshift and optical spectroscopic reference catalogue for the local extragalactic Universe in the southern sky for the coming decade.
Galaxy and mass assembly (GAMA): the consistency of GAMA and WISE derived mass-to-light ratios
Publisher: Oxford University Press (OUP)
Date: 13-09-2017
Photonic ring resonator filters for astronomical OH suppression
Publisher: The Optical Society
Date: 27-06-2017
DOI: 10.1364/OE.25.015868
Space photonics: A new era of space instrumentation
Publisher: IEEE
Date: 08-2011
Multi-mode to single-mode conversion in a 61 port Photonic Lantern
Publisher: Optica Publishing Group
Date: 22-02-2010
DOI: 10.1364/OE.18.004673
Is the Milky Way still breathing? RAVE-Gaia streaming motions
Publisher: Oxford University Press (OUP)
Date: 05-01-2018
The Southern Stellar Stream Spectroscopic Survey (S5): Chemical Abundances of Seven Stellar Streams
Publisher: American Astronomical Society
Date: 24-09-2020
The rich are different: Evidence from the RAVE Survey for Stellar Radial Migration
Publisher: Oxford University Press (OUP)
Date: 24-01-2015
Magnetized High Velocity Clouds in the Galactic Halo: A New Distance Constraint
Publisher: American Astronomical Society
Date: 11-08-2017
The mass–metallicity relation revisited with CALIFA
Publisher: Oxford University Press (OUP)
Date: 04-2017
DOI: 10.1093/MNRAS/STX808
CHROMOSPHERICALLY ACTIVE STARS IN THE RADIAL VELOCITY EXPERIMENT (RAVE) SURVEY. I. THE CATALOG
Publisher: American Astronomical Society
Date: 07-10-2013
Galaxy and Mass Assembly (GAMA): The stellar mass budget by galaxy type
Publisher: Oxford University Press (OUP)
Date: 02-2016
The GALAH survey: a new constraint on cosmological lithium and Galactic lithium evolution from warm dwarf stars
Publisher: Oxford University Press (OUP)
Date: 08-06-2202
Abstract: Lithium depletion and enrichment in the cosmos is not yet well understood. To help tighten constraints on stellar and Galactic evolution models, we present the largest high-resolution analysis of Li abundances A(Li) to date, with results for over $100\\, 000$ GALAH (Galactic Archeology with HERMES) field stars spanning effective temperatures $5900\\, \\mathrm{K} \\lesssim T_{\\mathrm{eff}}\\lesssim 7000\\, \\mathrm{K}$ and metallicities −3 ≲ [Fe/H] ≲ +0.5. We separated these stars into two groups, on the warm and cool sides of the so-called Li dip, a localized region of the Kiel diagram wherein lithium is severely depleted. We discovered that stars in these two groups show similar trends in the A(Li)–[Fe/H] plane, but with a roughly constant offset in A(Li) of $0.4\\, \\mathrm{dex}$, the warm group having higher Li abundances. At $\\rm [Fe/H]\\gtrsim -0.5$, a significant increase in Li abundance with increasing metallicity is evident in both groups, signalling the onset of significant Galactic production. At lower metallicity, stars in the cool group sit on the Spite plateau, showing a reduced lithium of around $0.4\\, \\mathrm{dex}$ relative to the primordial value predicted from big bang nucleosynthesis (BBN). However, stars in the warm group between [Fe/H] = −1.0 and −0.5 form an elevated plateau that is largely consistent with the BBN prediction. This may indicate that these stars in fact preserve the primordial Li produced in the early Universe.
The Large‐Scale Bipolar Wind in the Galactic Center
Publisher: American Astronomical Society
Date: 2003
DOI: 10.1086/344573
The SAMI Galaxy Survey: Gas streaming and dynamical M/L in rotationally supported systems
Publisher: Oxford University Press (OUP)
Date: 23-12-2016
Discovery of a nearby 1700 km s−1 star ejected from the Milky Way by Sgr A*
Publisher: Oxford University Press (OUP)
Date: 04-11-2019
Abstract: We present the serendipitous discovery of the fastest main-sequence hyper-velocity star (HVS) by the Southern Stellar Stream Spectroscopic Survey (S5). The star S5-HVS1 is a ∼2.35 M⊙ A-type star located at a distance of ∼9 kpc from the Sun and has a heliocentric radial velocity of 1017 ± 2.7 $\\mathrm{\\, km\\, s^{-1}}$ without any signature of velocity variability. The current 3D velocity of the star in the Galactic frame is 1755 ± 50 $\\mathrm{\\, km\\, s^{-1}}$. When integrated backwards in time, the orbit of the star points unambiguously to the Galactic Centre, implying that S5-HVS1 was kicked away from Sgr A* with a velocity of ∼1800 $\\mathrm{\\, km\\, s^{-1}}$ and travelled for 4.8 Myr to its current location. This is so far the only HVS confidently associated with the Galactic Centre. S5-HVS1 is also the first hyper-velocity star to provide constraints on the geometry and kinematics of the Galaxy, such as the Solar motion Vy,⊙ = 246.1 ± 5.3 $\\mathrm{\\, km\\, s^{-1}}$ or position R0 = 8.12 ± 0.23 kpc. The ejection trajectory and transit time of S5-HVS1 coincide with the orbital plane and age of the annular disc of young stars at the Galactic Centre, and thus may be linked to its formation. With the S5-HVS1 ejection velocity being almost twice the velocity of other hyper-velocity stars previously associated with the Galactic Centre, we question whether they have been generated by the same mechanism or whether the ejection velocity distribution has been constant over time.
Galaxy And Mass Assembly: accurate panchromatic photometry from optical priors using lambdar
Publisher: Oxford University Press (OUP)
Date: 12-04-2016
DOI: 10.1093/MNRAS/STW832
H-ATLAS/GAMA: the nature and characteristics of optically red galaxies detected at submillimetre wavelengths
Publisher: Oxford University Press (OUP)
Date: 30-12-2015
The SAMI Galaxy Survey: embedded discs and radial trends in outer dynamical support across the Hubble sequence
Publisher: Oxford University Press (OUP)
Date: 02-08-2018
The GALAH+ Survey: A new library of observed stellar spectra improves radial velocities and hints at motions within M67
Publisher: Oxford University Press (OUP)
Date: 20-09-2021
Abstract: GALAH+ is a magnitude-limited survey of high resolution stellar spectra obtained by the HERMES spectrograph at the Australian Astronomical Observatory. Its third data release provides reduced spectra with new derivations of stellar parameters and abundances of 30 chemical elements for 584,015 dwarfs and giants, 88 per cent of them in the Gaia magnitude range 11 & G & 14. Here we use these improved values of stellar parameters to build a library of observed spectra which is useful to study variations of in idual spectral lines with stellar parameters. This and other improvements are used to derive radial velocities with uncertainties which are generally within 0.1 km s−1 or ∼25 per cent smaller than in the previous release. Median differences in radial velocities measured here and by the Gaia DR2 or APOGEE DR16 surveys are smaller than 30 m s−1, a larger offset is present only for Gaia measurements of giant stars. We identify 4483 stars with intrinsically variable velocities and 225 stars for which the velocity stays constant over ≥3 visits spanning more than a year. The combination of radial velocities from GALAH+ with distances and sky plane motions from Gaia enables studies of dynamics within streams and clusters. For ex le, we estimate that the open cluster M67 has a total mass of ∼3300 M⊙ and its outer parts seem to be expanding, though astrometry with a larger time-span than currently available from Gaia eDR3 is needed to judge if the latter result is real.
Holistic spectroscopy: complete reconstruction of a wide-field, multiobject spectroscopic image using a photonic comb
Publisher: Oxford University Press (OUP)
Date: 13-08-2018
A RAVE investigation on Galactic open clusters: II. Open cluster pairs, groups and complexes
Publisher: EDP Sciences
Date: 04-2017
Hector: A modular integral field spectrograph instrument for the Anglo-Australian Telescope
Publisher: SPIE
Date: 06-07-2018
DOI: 10.1117/12.2309893
Galaxy And Mass Assembly (GAMA): $\mathcal {M_\star }\text{--}R_{\rm e}$ relations ofz= 0 bulges, discs and spheroids
Publisher: Oxford University Press (OUP)
Date: 06-07-2016
Galaxy And Mass Assembly (GAMA): the 0.013 < z < 0.1 cosmic spectral energy distribution from 0.1 m to 1 mm
Publisher: Oxford University Press (OUP)
Date: 21-12-2012
Asymmetric metallicity patterns in the stellar velocity space with RAVE
Publisher: EDP Sciences
Date: 28-04-2017
A tunable Lyot filter at prime focus: A method for tracing supercluster scales at z ∼ 1
Publisher: American Astronomical Society
Date: 20-12-2001
DOI: 10.1086/323770
The RAVE survey: Constraining the local Galactic escape speed
Publisher: Oxford University Press (OUP)
Date: 08-2007
THE LONG-TERM EVOLUTION OF THE GALACTIC DISK TRACED BY DISSOLVING STAR CLUSTERS
Publisher: American Astronomical Society
Date: 18-03-2010
The SAMI galaxy survey: stellar population radial gradients in early-type galaxies
Publisher: Oxford University Press (OUP)
Date: 06-08-2019
Abstract: We study the internal radial gradients of the stellar populations in a s le comprising 522 early-type galaxies (ETGs) from the SAMI (Sydney-AAO Multi-object Integral field spectrograph) Galaxy Survey. We stack the spectra of in idual spaxels in radial bins, and derive basic stellar population properties: total metallicity ([Z/H]), [Mg/Fe], [C/Fe] and age. The radial gradient (∇) and central value of the fits (evaluated at Re/4) are compared against a set of six observables that may act as drivers of the trends. We find that velocity dispersion (σ) – or, equivalently gravitational potential – is the dominant driver of the chemical composition gradients. Surface mass density is also correlated with the trends, especially with stellar age. The decrease of ∇[Mg/Fe] with increasing σ is contrasted by a rather shallow dependence of ∇[Z/H] with σ (although this radial gradient is overall rather steep). This result, along with a shallow age slope at the massive end, imposes a substantial constraint on the progenitors of the populations that contribute to the formation of the outer envelopes of ETGs. The SAMI s le is split, by design, between ‘field’ and cluster galaxies. Only weak environment-related differences are found, most notably a stronger dependence of central total metallicity ([Z/H]e4) with σ, along with a marginal trend of ∇[Z/H] to steepen in cluster galaxies, a result that is not followed by [Mg/Fe]. The results presented here serve as stringent constraints on numerical models of the formation and evolution of ETGs.
A complex multi-notch astronomical filter to suppress the bright infrared sky
Publisher: Springer Science and Business Media LLC
Date: 06-12-2011
DOI: 10.1038/NCOMMS1584
Abstract: A long-standing and profound problem in astronomy is the difficulty in obtaining deep near-infrared observations due to the extreme brightness and variability of the night sky at these wavelengths. A solution to this problem is crucial if we are to obtain the deepest possible observations of the early Universe, as redshifted starlight from distant galaxies appears at these wavelengths. The atmospheric emission between 1,000 and 1,800 nm arises almost entirely from a forest of extremely bright, very narrow hydroxyl emission lines that varies on timescales of minutes. The astronomical community has long envisaged the prospect of selectively removing these lines, while retaining high throughput between them. Here we demonstrate such a filter for the first time, presenting results from the first on-sky tests. Its use on current 8 m telescopes and future 30 m telescopes will open up many new research avenues in the years to come.
Galaxy And Mass Assembly (GAMA): the environments of high- and low-excitation radio galaxies
Publisher: Oxford University Press (OUP)
Date: 15-05-2017
OSIRIS tunable imager and spectrograph for the GTC. Instrument status
Publisher: SPIE
Date: 07-03-2003
DOI: 10.1117/12.460913
Galaxy And Mass Assembly (GAMA): stellar mass functions by Hubble type
Publisher: Oxford University Press (OUP)
Date: 29-08-2014
First light results from the Hermes spectrograph at the AAT
Publisher: SPIE
Date: 08-07-2014
DOI: 10.1117/12.2055595
Tracing the Milky Way’s Vestigial Nuclear Jet
Publisher: American Astronomical Society
Date: 12-2021
Abstract: MeerKAT radio continuum and XMM-Newton X-ray images have recently revealed a spectacular bipolar channel at the Galactic Center that spans several degrees (∼0.5 kpc). An intermittent jet likely formed this channel and is consistent with earlier evidence of a sustained, Seyfert-level outburst fueled by black hole accretion onto Sgr A* several Myr ago. Therefore, to trace a now weak jet that perhaps penetrated, deflected, and percolated along multiple paths through the interstellar medium, relevant interactions are identified and quantified in archival X-ray images, Hubble Space Telescope Paschen α images and Atacama Large Millimeter/submillimeter Array millimeter-wave spectra, and new SOAR telescope IR spectra. Hydrodynamical simulations are used to show how a nuclear jet can explain these structures and inflate the ROSAT/eROSITA X-ray and Fermi γ -ray bubbles that extend ± 75° from the Galactic plane. Thus, our Galactic outflow has features in common with energetic, jet-driven structures in the prototypical Seyfert galaxy NGC 1068.
PRAXIS: Low thermal emission high efficiency OH suppressed fibre spectrograph
Publisher: SPIE
Date: 28-07-2014
DOI: 10.1117/12.2055597
The GALAH survey: effective temperature calibration from the InfraRed Flux Method in the Gaia system
Publisher: Oxford University Press (OUP)
Date: 10-08-2021
Abstract: In order to accurately determine stellar properties, knowledge of the effective temperature of stars is vital. We implement Gaia and 2MASS photometry in the InfraRed Flux Method and apply it to over 360 000 stars across different evolutionary stages in the GALAH DR3 survey. We derive colour-effective temperature relations that take into account the effect of metallicity and surface gravity over the range $4000\\, \\rm {K}\\lesssim T_{\\rm {eff}}\\lesssim 8000\\, \\rm {K}$, from very metal-poor stars to supersolar metallicities. The internal uncertainty of these calibrations is of order 40–80 K depending on the colour combination used. Comparison against solar-twins, Gaia benchmark stars, and the latest interferometric measurements validates the precision and accuracy of these calibrations from F to early M spectral types. We assess the impact of various sources of uncertainties, including the assumed extinction law, and provide guidelines to use our relations. Robust solar colours are also derived.
Velocity-resolved Fabry-Perot imaging of molecular hydrogen emission in OMC-1
Publisher: Oxford University Press (OUP)
Date: 11-08-1997
The GALAH survey: a catalogue of carbon-enhanced stars and CEMP candidates
Publisher: Oxford University Press (OUP)
Date: 22-11-2019
Galaxy and mass assembly: luminosity and stellar mass functions in GAMA groups
Publisher: Oxford University Press (OUP)
Date: 21-09-2020
Abstract: How do galaxy properties (such as stellar mass, luminosity, star formation rate, and morphology) and their evolution depend on the mass of their host dark matter halo? Using the Galaxy and Mass Assembly group catalogue, we address this question by exploring the dependence on host halo mass of the luminosity function (LF) and stellar mass function (SMF) for grouped galaxies sub ided by colour, morphology, and central/satellite. We find that spheroidal galaxies in particular dominate the bright and massive ends of the LF and SMF, respectively. More massive haloes host more massive and more luminous central galaxies. The satellites LF and SMF, respectively, show a systematic brightening of characteristic magnitude, and increase in characteristic mass, with increasing halo mass. In contrast to some previous results, the faint-end and low-mass slopes show little systematic dependence on halo mass. Semi-analytic models and simulations show similar or enhanced dependence of central mass and luminosity on halo mass. Faint and low-mass simulated satellite galaxies are remarkably independent of halo mass, but the most massive satellites are more common in more massive groups. In the first investigation of low-redshift LF and SMF evolution in group environments, we find that the red/blue ratio of galaxies in groups has increased since redshift z ≈ 0.3 relative to the field population. This observation strongly suggests that quenching of star formation in galaxies as they are accreted into galaxy groups is a significant and ongoing process.
The GALAH survey: characterization of emission-line stars with spectral modelling using autoencoders
Publisher: Oxford University Press (OUP)
Date: 10-12-2021
Abstract: We present a neural network autoencoder structure that is able to extract essential latent spectral features from observed spectra and then reconstruct a spectrum from those features. Because of the training with a set of unpeculiar spectra, the network is able to reproduce a spectrum of high signal-to-noise ratio that does not show any spectral peculiarities, even if they are present in an observed spectrum. Spectra generated in this manner were used to identify various emission features among spectra acquired by multiple surveys using the HERMES spectrograph at the Anglo-Australian telescope. Emission features were identified by a direct comparison of the observed and generated spectra. Using the described comparison procedure, we discovered 10 364 candidate spectra with varying intensities (from partially filled-in to well above the continuum) of the Hα/Hβ emission component, produced by different physical mechanisms. A fraction of these spectra belong to the repeated observation that shows temporal variability in their emission profile. Among the emission spectra, we find objects that feature contributions from a nearby rarefied gas (identified through the emission of [N ii] and [S ii] lines) that was identified in 4004 spectra, which were not all identified as having Hα emission. The positions of identified emission-line objects coincide with multiple known regions that harbour young stars. Similarly, detected nebular emission spectra coincide with visually prominent nebular clouds observable in the red all-sky photographic composites.
GAMA/H-ATLAS: a meta-analysis of SFR indicators – comprehensive measures of the SFR–M*relation and cosmic star formation history atz < 0.4
Publisher: Oxford University Press (OUP)
Date: 07-06-2016
IMF shape constraints from stellar populations and dynamics from CALIFA
Publisher: Oxford University Press (OUP)
Date: 05-10-2016
ERASMUS-F: Pathfinder for an E-ELT 3D-instrumentation
Publisher: SPIE
Date: 16-07-2010
DOI: 10.1117/12.857007
The SAMI galaxy survey: Shocks and outflows in a normal star-forming galaxy
Publisher: Oxford University Press (OUP)
Date: 18-09-2014
Galaxy And Mass Assembly (GAMA): the galaxy stellar mass function to z = 0.1 from the r-band selected equatorial regions
Publisher: Oxford University Press (OUP)
Date: 11-05-2017
Jet‐ and Wind‐driven Ionized Outflows in the Superbubble and Star‐forming Disk of NGC 3079
Publisher: American Astronomical Society
Date: 07-2001
DOI: 10.1086/321481
SARS-CoV-2 vaccination modelling for safe surgery to save lives: data from an international prospective cohort study
Publisher: Oxford University Press (OUP)
Date: 24-03-2021
DOI: 10.1093/BJS/ZNAB101
Abstract: Preoperative SARS-CoV-2 vaccination could support safer elective surgery. Vaccine numbers are limited so this study aimed to inform their prioritization by modelling. The primary outcome was the number needed to vaccinate (NNV) to prevent one COVID-19-related death in 1 year. NNVs were based on postoperative SARS-CoV-2 rates and mortality in an international cohort study (surgical patients), and community SARS-CoV-2 incidence and case fatality data (general population). NNV estimates were stratified by age (18–49, 50–69, 70 or more years) and type of surgery. Best- and worst-case scenarios were used to describe uncertainty. NNVs were more favourable in surgical patients than the general population. The most favourable NNVs were in patients aged 70 years or more needing cancer surgery (351 best case 196, worst case 816) or non-cancer surgery (733 best case 407, worst case 1664). Both exceeded the NNV in the general population (1840 best case 1196, worst case 3066). NNVs for surgical patients remained favourable at a range of SARS-CoV-2 incidence rates in sensitivity analysis modelling. Globally, prioritizing preoperative vaccination of patients needing elective surgery ahead of the general population could prevent an additional 58 687 (best case 115 007, worst case 20 177) COVID-19-related deaths in 1 year. As global roll out of SARS-CoV-2 vaccination proceeds, patients needing elective surgery should be prioritized ahead of the general population.
Effects of pre‐operative isolation on postoperative pulmonary complications after elective surgery: an international prospective cohort study
Publisher: Wiley
Date: 09-08-2021
DOI: 10.1111/ANAE.15560
Abstract: We aimed to determine the impact of pre‐operative isolation on postoperative pulmonary complications after elective surgery during the global SARS‐CoV‐2 pandemic. We performed an international prospective cohort study including patients undergoing elective surgery in October 2020. Isolation was defined as the period before surgery during which patients did not leave their house or receive visitors from outside their household. The primary outcome was postoperative pulmonary complications, adjusted in multivariable models for measured confounders. Pre‐defined sub‐group analyses were performed for the primary outcome. A total of 96,454 patients from 114 countries were included and overall, 26,948 (27.9%) patients isolated before surgery. Postoperative pulmonary complications were recorded in 1947 (2.0%) patients of which 227 (11.7%) were associated with SARS‐CoV‐2 infection. Patients who isolated pre‐operatively were older, had more respiratory comorbidities and were more commonly from areas of high SARS‐CoV‐2 incidence and high‐income countries. Although the overall rates of postoperative pulmonary complications were similar in those that isolated and those that did not (2.1% vs 2.0%, respectively), isolation was associated with higher rates of postoperative pulmonary complications after adjustment (adjusted OR 1.20, 95%CI 1.05–1.36, p = 0.005). Sensitivity analyses revealed no further differences when patients were categorised by: pre‐operative testing use of COVID‐19‐free pathways or community SARS‐CoV‐2 prevalence. The rate of postoperative pulmonary complications increased with periods of isolation longer than 3 days, with an OR (95%CI) at 4–7 days or ≥ 8 days of 1.25 (1.04–1.48), p = 0.015 and 1.31 (1.11–1.55), p = 0.001, respectively. Isolation before elective surgery might be associated with a small but clinically important increased risk of postoperative pulmonary complications. Longer periods of isolation showed no reduction in the risk of postoperative pulmonary complications. These findings have significant implications for global provision of elective surgical care.
The effect of the deforming dark matter haloes of the Milky Way and the Large Magellanic Cloud on the Orphan–Chenab stream
Publisher: Oxford University Press (OUP)
Date: 28-10-2022
Abstract: It has recently been shown that the Large Magellanic Cloud (LMC) has a substantial effect on the Milky Way’s stellar halo and stellar streams. Here, we explore how deformations of the Milky Way and LMC’s dark matter haloes affect stellar streams, and whether these effects are observable. In particular, we focus on the Orphan–Chenab (OC) stream which passes particularly close to the LMC and spans a large portion of the Milky Way’s halo. We represent the Milky Way–LMC system using basis function expansions that capture their evolution in an N-body simulation. We present the properties of this system, such as the evolution of the densities and force fields of each galaxy. The OC stream is evolved in this time-dependent, deforming potential, and we investigate the effects of the various moments of the Milky Way and the LMC. We find that the simulated OC stream is strongly influenced by the deformations of both the Milky Way and the LMC and that this effect is much larger than current observational errors. In particular, the Milky Way dipole has the biggest impact on the stream, followed by the evolution of the LMC’s monopole, and the LMC’s quadrupole. Detecting these effects would confirm a key prediction of collisionless, cold dark matter, and would be a powerful test of alternative dark matter and alternative gravity models.
The R-Process Alliance: First Release from the Northern Search for r-process-enhanced Metal-poor Stars in the Galactic Halo
Publisher: American Astronomical Society
Date: 29-11-2018
Local stellar kinematics from RAVE data - I. Local standard of rest
Publisher: Oxford University Press (OUP)
Date: 2011
DIVISION H COMMISSION 33: STRUCTURE & DYNAMICS OF THE GALACTIC SYSTEM
Publisher: Cambridge University Press (CUP)
Date: 08-2015
DOI: 10.1017/S1743921316000946
Abstract: Research on the structure and dynamics of the Galactic System covers a large field of research, from formation scenarios to long-term evolution and secular processes. Today we speak of near-field cosmology where the oldest parts of the Galaxy are used to probe back to early times, e.g. studying the chemical signatures of the oldest star clusters and dwarf galaxies to learn about the byproducts of the first stars. Some of the most detailed work relates to the structure of the dark matter and baryons in order to compare with expectation from N-body models. Secular processes have been identified (e.g. stellar migration) where material within the Galaxy is being reorganized by dynamical resonances and feedback processes.
NGC 147, NGC 185 and CassII: A genetic approach to orbital properties, star formation and tidal debris
Publisher: Oxford University Press (OUP)
Date: 24-12-2016
The GALAH+ survey: Third data release
Publisher: Oxford University Press (OUP)
Date: 06-05-2021
Abstract: The ensemble of chemical element abundance measurements for stars, along with precision distances and orbit properties, provides high-dimensional data to study the evolution of the Milky Way. With this third data release of the Galactic Archaeology with HERMES (GALAH) survey, we publish 678 423 spectra for 588 571 mostly nearby stars (81.2 per cent of stars are within & kpc), observed with the HERMES spectrograph at the Anglo-Australian Telescope. This release (hereafter GALAH+ DR3) includes all observations from GALAH Phase 1 (bright, main, and faint survey, 70 per cent), K2-HERMES (17 per cent), TESS-HERMES (5 per cent), and a subset of ancillary observations (8 per cent) including the bulge and & stellar clusters. We derive stellar parameters Teff, log g, [Fe/H], vmic, vbroad, and vrad using our modified version of the spectrum synthesis code Spectroscopy Made Easy (sme) and 1D marcs model atmospheres. We break spectroscopic degeneracies in our spectrum analysis with astrometry from Gaia DR2 and photometry from 2MASS. We report abundance ratios [X/Fe] for 30 different elements (11 of which are based on non-LTE computations) covering five nucleosynthetic pathways. We describe validations for accuracy and precision, flagging of peculiar stars/measurements and recommendations for using our results. Our catalogue comprises 65 per cent dwarfs, 34 per cent giants, and 1 per cent other/unclassified stars. Based on unflagged chemical composition and age, we find 62 per cent young low-$\\alpha$, 9 per cent young high-$\\alpha$, 27 per cent old high-$\\alpha$, and 2 per cent stars with [Fe/H] ≤ −1. Based on kinematics, 4 per cent are halo stars. Several Value-Added-Catalogues, including stellar ages and dynamics, updated after Gaia eDR3, accompany this release and allow chrono-chemodynamic analyses, as we showcase.
A NEW SCALING RELATION FOR H II REGIONS IN SPIRAL GALAXIES: UNVEILING THE TRUE NATURE OF THE MASS-METALLICITY RELATION
Publisher: American Astronomical Society
Date: 22-08-2012
The survey for ionization in neutral gas galaxies. III. Diffuse, warm ionized medium and escape of ionizing radiation
Publisher: American Astronomical Society
Date: 06-2007
DOI: 10.1086/517867
Ultra high coupling efficiency from a single mode fiber to a high index contrast on-chip waveguide and complex waveguide Bragg gratings for spectral filtering
Publisher: IEEE
Date: 07-2015
Near- and mid-infrared imaging polarimetry of NGC 1068
Publisher: Oxford University Press (OUP)
Date: 02-1999
SARS‐CoV‐2 infection and venous thromboembolism after surgery: an international prospective cohort study
Publisher: Wiley
Date: 24-08-2021
DOI: 10.1111/ANAE.15563
Abstract: SARS‐CoV‐2 has been associated with an increased rate of venous thromboembolism in critically ill patients. Since surgical patients are already at higher risk of venous thromboembolism than general populations, this study aimed to determine if patients with peri‐operative or prior SARS‐CoV‐2 were at further increased risk of venous thromboembolism. We conducted a planned sub‐study and analysis from an international, multicentre, prospective cohort study of elective and emergency patients undergoing surgery during October 2020. Patients from all surgical specialties were included. The primary outcome measure was venous thromboembolism (pulmonary embolism or deep vein thrombosis) within 30 days of surgery. SARS‐CoV‐2 diagnosis was defined as peri‐operative (7 days before to 30 days after surgery) recent (1–6 weeks before surgery) previous (≥7 weeks before surgery) or none. Information on prophylaxis regimens or pre‐operative anti‐coagulation for baseline comorbidities was not available. Postoperative venous thromboembolism rate was 0.5% (666/123,591) in patients without SARS‐CoV‐2 2.2% (50/2317) in patients with peri‐operative SARS‐CoV‐2 1.6% (15/953) in patients with recent SARS‐CoV‐2 and 1.0% (11/1148) in patients with previous SARS‐CoV‐2. After adjustment for confounding factors, patients with peri‐operative (adjusted odds ratio 1.5 (95%CI 1.1–2.0)) and recent SARS‐CoV‐2 (1.9 (95%CI 1.2–3.3)) remained at higher risk of venous thromboembolism, with a borderline finding in previous SARS‐CoV‐2 (1.7 (95%CI 0.9–3.0)). Overall, venous thromboembolism was independently associated with 30‐day mortality (5.4 (95%CI 4.3–6.7)). In patients with SARS‐CoV‐2, mortality without venous thromboembolism was 7.4% (319/4342) and with venous thromboembolism was 40.8% (31/76). Patients undergoing surgery with peri‐operative or recent SARS‐CoV‐2 appear to be at increased risk of postoperative venous thromboembolism compared with patients with no history of SARS‐CoV‐2 infection. Optimal venous thromboembolism prophylaxis and treatment are unknown in this cohort of patients, and these data should be interpreted accordingly.
The Asymmetric Wind in M82
Publisher: American Astronomical Society
Date: 20-01-1998
DOI: 10.1086/305108
Towards a new classification of galaxies: principal component analysis of CALIFA circular velocity curves
Publisher: Oxford University Press (OUP)
Date: 12-04-2017
DOI: 10.1093/MNRAS/STX901
Concepts for a high resolution multi-object spectrograph for galactic archeology on the Anglo-Australian Telescope
Publisher: SPIE
Date: 12-07-2008
DOI: 10.1117/12.788549
The survey for ionization in neutral gas galaxies. I. Description and initial results
Publisher: American Astronomical Society
Date: 07-2006
DOI: 10.1086/504685
Instruments without optics: An integrated photonic spectrograph
Publisher: SPIE
Date: 14-06-2006
DOI: 10.1117/12.670931
Nineteen-port photonic lantern with multimode delivery fiber
Publisher: The Optical Society
Date: 03-02-2012
DOI: 10.1364/OL.37.000452
The SAMI galaxy survey
Publisher: Oxford University Press (OUP)
Date: 21-11-2019
The survey for ionization in neutral gas galaxies. II. The star formation rate density of the local universe
Publisher: American Astronomical Society
Date: 20-09-2006
DOI: 10.1086/504681
The GALAH survey and Gaia DR2: (non-)existence of five sparse high-latitude open clusters
Publisher: Oxford University Press (OUP)
Date: 13-08-2018
Galaxy And Mass Assembly (GAMA): the dependence of the galaxy luminosity function on environment, redshift and colour
Publisher: Oxford University Press (OUP)
Date: 15-10-2014
The GALAH survey: accurate radial velocities and library of observed stellar template spectra
Publisher: Oxford University Press (OUP)
Date: 23-08-2018
ASKAP commissioning observations of the GAMA 23 field
Publisher: Cambridge University Press (CUP)
Date: 2019
DOI: 10.1017/PASA.2019.16
Abstract: We have observed the G23 field of the Galaxy AndMass Assembly (GAMA) survey using the Australian Square Kilometre Array Pathfinder (ASKAP) in its commissioning phase to validate the performance of the telescope and to characterise the detected galaxy populations. This observation covers ~48 deg 2 with synthesised beam of 32.7 arcsec by 17.8 arcsec at 936MHz, and ~39 deg 2 with synthesised beam of 15.8 arcsec by 12.0 arcsec at 1320MHz. At both frequencies, the root-mean-square (r.m.s.) noise is ~0.1 mJy/beam. We combine these radio observations with the GAMA galaxy data, which includes spectroscopy of galaxies that are i-band selected with a magnitude limit of 19.2. Wide-field Infrared Survey Explorer (WISE) infrared (IR) photometry is used to determine which galaxies host an active galactic nucleus (AGN). In properties including source counts, mass distributions, and IR versus radio luminosity relation, the ASKAP-detected radio sources behave as expected. Radio galaxies have higher stellar mass and luminosity in IR, optical, and UV than other galaxies. We apply optical and IR AGN diagnostics and find that they disagree for ~30% of the galaxies in our s le. We suggest possible causes for the disagreement. Some cases can be explained by optical extinction of the AGN, but for more than half of the cases we do not find a clear explanation. Radio sources aremore likely (~6%) to have an AGN than radio quiet galaxies (~1%), but the majority of AGN are not detected in radio at this sensitivity.
1x11 few-mode fiber wavelength selective switch using photonic lanterns
Publisher: The Optical Society
Date: 27-01-2014
DOI: 10.1364/OE.22.002216
The SAMI galaxy survey
Publisher: Oxford University Press (OUP)
Date: 02-07-2020
Abstract: It has been proposed that S0 galaxies are either fading spirals or the result of galaxy mergers. The relative contribution of each pathway and the environments in which they occur remain unknown. Here, we investigate stellar and gas kinematics of 219 S0s in the SAMI Survey to look for signs of multiple formation pathways occurring across the full range of environments. We identify a large range of rotational support in their stellar kinematics, which correspond to ranges in their physical structure. We find that pressure-supported S0s with v/σ below 0.5 tend to be more compact and feature misaligned stellar and gas components, suggesting an external origin for their gas. We postulate that these S0s are consistent with being formed through a merger process. Meanwhile, comparisons of ellipticity, stellar mass, and Sérsic index distributions with spiral galaxies show that the rotationally supported S0s with v/σ above 0.5 are more consistent with a faded spiral origin. In addition, a simulated merger pathway involving a compact elliptical and gas-rich satellite results in an S0 that lies within the pressure-supported group. We conclude that two S0 formation pathways are active, with mergers dominating in isolated galaxies and small groups, and the faded spiral pathway being most prominent in large groups ($10^{13}\\lt \\rm {M_{halo}}\\lt 10^{14}$).
Mapping the aberrations of a wide-field spectrograph using a photonic comb
Publisher: The Optical Society
Date: 26-06-2017
DOI: 10.1364/OE.25.015614
Galaxy And Mass Assembly: the evolution of the cosmic spectral energy distribution from z = 1 to z = 0
Publisher: Oxford University Press (OUP)
Date: 25-05-2017
The 2dF-SDSS LRG and QSO Survey: evolution of the clustering of luminous red galaxies sincez= 0.6
Publisher: Oxford University Press (OUP)
Date: 07-2008
The SAMI Galaxy Survey: The contribution of different kinematic classes to the stellar mass function of nearby galaxies
Publisher: Oxford University Press (OUP)
Date: 31-10-2019
Abstract: We use the complete Sydney-AAO Multi-object Integral field spectrograph (SAMI) Galaxy Survey to determine the contribution of slow rotators, as well as different types of fast rotators, to the stellar mass function of galaxies in the local Universe. We use stellar kinematics not only to discriminate between fast and slow rotators, but also to distinguish between dynamically cold systems (i.e., consistent with intrinsic axis ratios .3) and systems including a prominent dispersion-supported bulge. We show that fast rotators account for more than $80\\%$ of the stellar mass budget of nearby galaxies, confirming that their number density overwhelms that of slow rotators at almost all masses from 109 to 1011.5M⊙. Most importantly, dynamically cold disks contribute to at least $25\\%$ of the stellar mass budget of the local Universe, significantly higher than what is estimated from visual morphology alone. For stellar masses up to 1010.5M⊙, this class makes up $ =30\\%$ of the galaxy population in each stellar mass bin. The fact that many galaxies that are visually classified as having two-components have stellar spin consistent with dynamically cold disks suggests that the inner component is either rotationally-dominated (e.g., bar, pseudo-bulge) or has little effect on the global stellar kinematics of galaxies.
Arrayed waveguide grating spectrometers for astronomical applications: new results
Publisher: The Optical Society
Date: 18-07-2017
DOI: 10.1364/OE.25.017918
The GALAH survey: temporal chemical enrichment of the galactic disc
Publisher: Oxford University Press (OUP)
Date: 12-11-2020
Abstract: We present isochrone ages and initial bulk metallicities ($\\rm [Fe/H]_{bulk}$, by accounting for diffusion) of 163 722 stars from the GALAH Data Release 2, mainly composed of main-sequence turn-off stars and subgiants ($7000\\, \\mathrm{ K}& T_{\\mathrm{ eff}}& 4000\\, \\mathrm{ K}$ and $\\log g& $ dex). The local age–metallicity relationship (AMR) is nearly flat but with significant scatter at all ages the scatter is even higher when considering the observed surface abundances. After correcting for selection effects, the AMR appears to have intrinsic structures indicative of two star formation events, which we speculate are connected to the thin and thick discs in the solar neighbourhood. We also present abundance ratio trends for 16 elements as a function of age, across different $\\rm [Fe/H]_{bulk}$ bins. In general, we find the trends in terms of [X/Fe] versus age from our far larger s le to be compatible with studies based on small (∼100 stars) s les of solar twins, but we now extend them to both sub- and supersolar metallicities. The α-elements show differing behaviour: the hydrostatic α-elements O and Mg show a steady decline with time for all metallicities, while the explosive α-elements Si, Ca, and Ti are nearly constant during the thin-disc epoch (ages $\\lesssim \\! 12$ Gyr). The s-process elements Y and Ba show increasing [X/Fe] with time while the r-process element Eu has the opposite trend, thus favouring a primary production from sources with a short time delay such as core-collapse supernovae over long-delay events such as neutron star mergers.
Single mode, extreme precision doppler spectrographs
Publisher: Cambridge University Press (CUP)
Date: 08-2012
DOI: 10.1017/S1743921313013264
Abstract: The ‘holy grail’ of exoplanet research today is the detection of an earth-like planet: a rocky planet in the habitable zone around a main-sequence star. Extremely precise Doppler spectroscopy is an indispensable tool to find and characterize earth-like planets however, to find these planets around solar-type stars, we need nearly one order of magnitude better radial velocity (RV) precision than the best current spectrographs provide. Recent developments in astrophotonics (Bland-Hawthorn & Horton 2006, Bland-Hawthorn et al . 2010) and adaptive optics (AO) enable single mode fiber (SMF) fed, high resolution spectrographs, which can realize the next step in precision. SMF feeds have intrinsic advantages over multimode fiber or slit coupled spectrographs: The intensity distribution at the fiber exit is extremely stable, and as a result the line spread function of a well-designed spectrograph is fully decoupled from input coupling conditions, like guiding or seeing variations (Ihle et al . 2010). Modal noise, a limiting factor in current multimode fiber fed instruments (Baudrand & Walker 2001), can be eliminated by proper design, and the diffraction limited input to the spectrograph allows for very compact instrument designs, which provide excellent optomechanical stability. A SMF is the ideal interface for new, very precise wavelength calibrators, like laser frequency combs (Steinmetz et al . 2008, Osterman et al . 2012), or SMF based Fabry-Perot Etalons (Halverson et al . 2013). At near infrared wavelengths, these technologies are ready to be implemented in on-sky instruments, or already in use. We discuss a novel concept for such a spectrograph.
Beating the classical limit: A diffraction-limited spectrograph for an arbitrary input beam
Publisher: The Optical Society
Date: 24-10-2013
DOI: 10.1364/OE.21.026103
Timing of surgery following SARS‐CoV‐2 infection: an international prospective cohort study
Publisher: Wiley
Date: 09-03-2021
DOI: 10.1111/ANAE.15458
Abstract: Peri‐operative SARS‐CoV‐2 infection increases postoperative mortality. The aim of this study was to determine the optimal duration of planned delay before surgery in patients who have had SARS‐CoV‐2 infection. This international, multicentre, prospective cohort study included patients undergoing elective or emergency surgery during October 2020. Surgical patients with pre‐operative SARS‐CoV‐2 infection were compared with those without previous SARS‐CoV‐2 infection. The primary outcome measure was 30‐day postoperative mortality. Logistic regression models were used to calculate adjusted 30‐day mortality rates stratified by time from diagnosis of SARS‐CoV‐2 infection to surgery. Among 140,231 patients (116 countries), 3127 patients (2.2%) had a pre‐operative SARS‐CoV‐2 diagnosis. Adjusted 30‐day mortality in patients without SARS‐CoV‐2 infection was 1.5% (95%CI 1.4–1.5). In patients with a pre‐operative SARS‐CoV‐2 diagnosis, mortality was increased in patients having surgery within 0–2 weeks, 3–4 weeks and 5–6 weeks of the diagnosis (odds ratio (95%CI) 4.1 (3.3–4.8), 3.9 (2.6–5.1) and 3.6 (2.0–5.2), respectively). Surgery performed ≥ 7 weeks after SARS‐CoV‐2 diagnosis was associated with a similar mortality risk to baseline (odds ratio (95%CI) 1.5 (0.9–2.1)). After a ≥ 7 week delay in undertaking surgery following SARS‐CoV‐2 infection, patients with ongoing symptoms had a higher mortality than patients whose symptoms had resolved or who had been asymptomatic (6.0% (95%CI 3.2–8.7) vs. 2.4% (95%CI 1.4–3.4) vs. 1.3% (95%CI 0.6–2.0), respectively). Where possible, surgery should be delayed for at least 7 weeks following SARS‐CoV‐2 infection. Patients with ongoing symptoms ≥ 7 weeks from diagnosis may benefit from further delay.
The K2 Galactic Archaeology Program Data Release 3: Age-abundance Patterns in C1–C8 and C10–C18
Publisher: American Astronomical Society
Date: 02-2022
Abstract: We present the third and final data release of the K2 Galactic Archaeology Program (K2 GAP) for C aigns C1–C8 and C10–C18. We provide asteroseismic radius and mass coefficients, κ R and κ M , for ∼19,000 red giant stars, which translate directly to radius and mass given a temperature. As such, K2 GAP DR3 represents the largest asteroseismic s le in the literature to date. K2 GAP DR3 stellar parameters are calibrated to be on an absolute parallactic scale based on Gaia DR2, with red giant branch and red clump evolutionary state classifications provided via a machine-learning approach. Combining these stellar parameters with GALAH DR3 spectroscopy, we determine asteroseismic ages with precisions of ∼20%–30% and compare age-abundance relations to Galactic chemical evolution models among both low- and high- α populations for α , light, iron-peak, and neutron-capture elements. We confirm recent indications in the literature of both increased Ba production at late Galactic times as well as significant contributions to r -process enrichment from prompt sources associated with, e.g., core-collapse supernovae. With an eye toward other Galactic archeology applications, we characterize K2 GAP DR3 uncertainties and completeness using injection tests, suggesting that K2 GAP DR3 is largely unbiased in mass/age, with uncertainties of 2.9% (stat.) ± 0.1% (syst.) and 6.7% (stat.) ± 0.3% (syst.) in κ R and κ M for red giant branch stars and 4.7% (stat.) ± 0.3% (syst.) and 11% (stat.) ± 0.9% (syst.) for red clump stars. We also identify percent-level asteroseismic systematics, which are likely related to the time baseline of the underlying data, and which therefore should be considered in TESS asteroseismic analysis.
NGC 922 - a new drop-through ring galaxy★
Publisher: Oxford University Press (OUP)
Date: 07-07-2006
The SAMI Galaxy Survey
Publisher: Oxford University Press (OUP)
Date: 30-11-2023
Chemical Homogeneity in the Hyades
Publisher: American Astronomical Society
Date: 2006
DOI: 10.1086/497968
The nature of the near-infrared interline sky background using fibre Bragg grating OH suppression
Publisher: Oxford University Press (OUP)
Date: 16-05-2013
DOI: 10.1093/MNRAS/STT677
The GALAH survey: A census of lithium-rich giant stars
Publisher: Oxford University Press (OUP)
Date: 14-05-2021
Abstract: We investigate the properties of 1262 red giant stars with high photospheric abundances of lithium observed by the GALAH and K2-HERMES surveys, and discuss them in the context of proposed mechanisms for lithium enrichment and re-depletion in giant stars. We confirm that Li-rich giants are rare, making up only 1.2 per cent of our giant star s le. We use stellar parameters from the third public data release from the GALAH survey and a Bayesian isochrone analysis to ide the s le into first-ascent red giant branch and red clump stars, and confirm these classifications using asteroseismic data from K2. We find that red clump stars are 2.5 times as likely to be lithium-rich as red giant branch stars, in agreement with other recent work. The probability for a star to be lithium-rich is affected by a number of factors, though the causality in those correlations is not entirely clear. We show for the first time that primary and secondary red clump stars have distinctly different lithium enrichment patterns. The data set discussed here is large and heterogeneous in terms of evolutionary phase, metallicity, rotation rate and mass. We expect that if the various mechanisms that have been proposed for lithium enrichment in evolved stars are in fact active, they should all contribute to this s le of lithium-rich giants at some level.
THE COS/UVES ABSORPTION SURVEY OF THE MAGELLANIC STREAM. I. ONE-TENTH SOLAR ABUNDANCES ALONG THE BODY OF THE STREAM
Publisher: American Astronomical Society
Date: 12-07-2013
A Kinematic Link Between Boxy Bulges, Stellar Bars, and Nuclear Activity in NGC 3079 and NGC 4388
Publisher: American Astronomical Society
Date: 11-1999
DOI: 10.1086/301095
Galaxy and Mass Assembly (GAMA): formation and growth of elliptical galaxies in the group environment
Publisher: Oxford University Press (OUP)
Date: 22-02-2017
DOI: 10.1093/MNRAS/STX441
The SAMI Galaxy Survey: The cluster redshift survey, target selection and cluster properties
Publisher: Oxford University Press (OUP)
Date: 08-03-2017
DOI: 10.1093/MNRAS/STX562
Post-inscription tuning of multicore fiber Bragg gratings
Publisher: SPIE
Date: 22-07-2016
DOI: 10.1117/12.2234245
THE COS/UVES ABSORPTION SURVEY OF THE MAGELLANIC STREAM. II. EVIDENCE FOR A COMPLEX ENRICHMENT HISTORY OF THE STREAM FROM THE FAIRALL 9 SIGHTLINE
Publisher: American Astronomical Society
Date: 12-07-2013
Galaxy And Mass Assembly (GAMA): the mass-metallicity relationship
Publisher: EDP Sciences
Date: 31-10-2012
The Magellanic system: The puzzle of the leading gas stream
Publisher: Oxford University Press (OUP)
Date: 14-06-2019
Abstract: The Magellanic Clouds (MCs) are the most massive gas-bearing systems falling into the Galaxy at the present epoch. They show clear signs of interaction, manifested in particular by the Magellanic Stream, a spectacular gaseous wake that trails from the MCs extending more than 150° across the sky. Ahead of the MCs is the ‘Leading Arm’ usually interpreted as the tidal counterpart of the Magellanic Stream, an assumption we now call into question. We revisit the formation of these gaseous structures in a first-infall scenario, including for the first time a Galactic model with a weakly magnetized, spinning hot corona. In agreement with previous studies, we recover the location and the extension of the Stream on the sky. In contrast, we find that the formation of the Leading Arm – that is otherwise present in models without a corona – is inhibited by the hydrodynamic interaction with the hot component. These results hold with or without coronal rotation or a weak, ambient magnetic field. Since the existence of the hot corona is well established, we are led to two possible interpretations: (i) the Leading Arm survives because the coronal density beyond 20 kpc is a factor ≳10 lower than required by conventional spheroidal coronal X-ray models, in line with recent claims of rapid coronal rotation or (ii) the ‘Leading Arm’ is cool gas trailing from a frontrunner, a satellite moving ahead of the MCs, consistent with its higher metallicity compared to the trailing stream. Both scenarios raise issues that we discuss.
Magnetic Fields in the Galactic Halo Restrict Fountain-driven Recycling and Accretion
Publisher: American Astronomical Society
Date: 21-09-2018
Volume phase holographic gratings: Polarization properties and diffraction efficiency
Publisher: IOP Publishing
Date: 05-2004
DOI: 10.1086/383622
The SAMI Galaxy Survey: first detection of a transition in spin orientation with respect to cosmic filaments in the stellar kinematics of galaxies
Publisher: Oxford University Press (OUP)
Date: 12-10-2020
Abstract: We present the first detection of mass-dependent galactic spin alignments with local cosmic filaments with & σ confidence using IFS kinematics. The 3D network of cosmic filaments is reconstructed on Mpc scales across GAlaxy and Mass Assembly fields using the cosmic web extractor DisPerSe. We assign field galaxies from the SAMI survey to their nearest filament segment in 3D and estimate the degree of alignment between SAMI galaxies’ kinematic spin axis and their nearest filament in projection. Low-mass galaxies align their spin with their nearest filament while higher mass counterparts are more likely to display an orthogonal orientation. The stellar transition mass from the first trend to the second is bracketed between $10^{10.4}$ and $10^{10.9}\\, \\mathrm{ M}_{\\odot }$, with hints of an increase with filament scale. Consistent signals are found in the Horizon-AGN cosmological hydrodynamic simulation. This supports a scenario of early angular momentum build-up in vorticity rich quadrants around filaments at low stellar mass followed by progressive flip of spins orthogonal to the cosmic filaments through mergers at high stellar mass. Conversely, we show that dark matter only simulations post-processed with a semi-analytical model treatment of galaxy formation struggles to reproduce this alignment signal. This suggests that gas physics is key in enhancing the galaxy-filament alignment.
Galaxy And Mass Assembly (GAMA): the unimodal nature of the dwarf galaxy population
Publisher: Oxford University Press (OUP)
Date: 02-12-2014
The local rotation curve of the Milky Way based on SEGUE and RAVE data
Publisher: EDP Sciences
Date: 06-2018
DOI: 10.1051/0004-6361/201731143
Abstract: Aims. We construct the rotation curve of the Milky Way in the extended solar neighbourhood using a s le of Sloan Extension for Galactic Understanding and Exploration (SEGUE) G-dwarfs. We investigate the rotation curve shape for the presence of any peculiarities just outside the solar radius as has been reported by some authors. Methods. Using the modified Strömberg relation and the most recent data from the RAdial Velocity Experiment (RAVE), we determine the solar peculiar velocity and the radial scale lengths for the three populations of different metallicities representing the Galactic thin disc. Subsequently, with the same binning in metallicity for the SEGUE G-dwarfs, we construct the rotation curve for a range of Galactocentric distances from 7 to 10 kpc. We approach this problem in a framework of classical Jeans analysis and derive the circular velocity by correcting the mean tangential velocity for the asymmetric drift in each distance bin. With SEGUE data we also calculate the radial scale length of the thick disc taking as known the derived peculiar motion of the Sun and the slope of the rotation curve. Results. The tangential component of the solar peculiar velocity is found to be V ⊙ = 4.47 ± 0.8 km s −1 and the corresponding scale lengths from the RAVE data are R d (0 [Fe/H] 0.2) = 2.07 ± 0.2 kpc, R d (−0.2 [Fe/H] 0) = 2.28 ± 0.26 kpc and R d (−0.5 [Fe/H] −0.2) = 3.05 ± 0.43 kpc. In terms of the asymmetric drift, the thin disc SEGUE stars are demonstrated to have dynamics similar to the thin disc RAVE stars, therefore the scale lengths calculated from the SEGUE s le have close values: R d (0 [Fe/H] 0.2) = 1.91 ± 0.23 kpc, R d (−0.2 [Fe/H] 0) = 2.51 ± 0.25 kpc and R d (−0.5 [Fe/H] −0.2) = 3.55 ± 0.42 kpc. The rotation curve constructed through SEGUE G-dwarfs appears to be smooth in the selected radial range 7 kpc R 10 kpc. The inferred power law index of the rotation curve is 0.033 ± 0.034, which corresponds to a local slope of dV c ∕ dR = 0.98 ± 1 km s −1 kpc −1 . The radial scale length of the thick disc is 2.05 kpc with no essential dependence on metallicity. Conclusions. The local kinematics of the thin disc rotation as determined in the framework of our new careful analysis does not favour the presence of a massive overdensity ring just outside the solar radius. We also find values for solar peculiar motion, radial scale lengths of thick disc, and three thin disc populations of different metallicities as a side result of this work.
The K2-HERMES Survey: age and metallicity of the thick disc
Publisher: Oxford University Press (OUP)
Date: 12-10-2019
Abstract: Asteroseismology is a promising tool to study Galactic structure and evolution because it can probe the ages of stars. Earlier attempts comparing seismic data from the Kepler satellite with predictions from Galaxy models found that the models predicted more low-mass stars compared to the observed distribution of masses. It was unclear if the mismatch was due to inaccuracies in the Galactic models, or the unknown aspects of the selection function of the stars. Using new data from the K2 mission, which has a well-defined selection function, we find that an old metal-poor thick disc, as used in previous Galactic models, is incompatible with the asteroseismic information. We use an importance-s ling framework, which takes the selection function into account, to fit for the metallicities of a population synthesis model using spectroscopic data. We show that spectroscopic measurements of [Fe/H] and [α/Fe] elemental abundances from the GALAH survey indicate a mean metallicity of log (Z/Z⊙) = −0.16 for the thick disc. Here Z is the effective solar-scaled metallicity, which is a function of [Fe/H] and [α/Fe]. With the revised disc metallicities, for the first time, the theoretically predicted distribution of seismic masses show excellent agreement with the observed distribution of masses. This indirectly verifies that the asteroseismic mass scaling relation is good to within five per cent. Assuming the asteroseismic scaling relations are correct, we estimate the mean age of the thick disc to be about 10 Gyr, in agreement with the traditional idea of an old α-enhanced thick disc.
Chemical gradients in the Milky Way from the RAVE data
Publisher: EDP Sciences
Date: 11-2013
Galaxy And Mass Assembly (GAMA): stellar mass estimates
Publisher: Oxford University Press (OUP)
Date: 18-11-2011
ULTRAFAINT DWARF GALAXIES - THE LOWEST-MASS RELICS FROM BEFORE REIONIZATION
Publisher: American Astronomical Society
Date: 09-07-2015
When is star formation episodic? A delay differential equation ‘negative feedback’ model
Publisher: Oxford University Press (OUP)
Date: 06-2008
New instrument concepts for observational cosmology
Publisher: Elsevier BV
Date: 06-2006
A NEW STELLAR CHEMO-KINEMATIC RELATION REVEALS THE MERGER HISTORY OF THE MILKY WAY DISK
Publisher: American Astronomical Society
Date: 06-01-2014
GAMA/H-ATLAS: the ultraviolet spectral slope and obscuration in galaxies
Publisher: Oxford University Press (OUP)
Date: 27-06-2011
Astrophysical signatures of leptonium
Publisher: Springer Science and Business Media LLC
Date: 2018
The OTELO survey
Publisher: EDP Sciences
Date: 14-10-2019
DOI: 10.1051/0004-6361/201833294
Abstract: Context . The evolution of galaxies through cosmic time is studied observationally by means of extragalactic surveys. The usefulness of these surveys is greatly improved by increasing the cosmological volume, in either depth or area, and by observing the same targets in different wavelength ranges. A multi-wavelength approach using different observational techniques can compensate for observational biases. Aims . The OTELO survey aims to provide the deepest narrow-band survey to date in terms of minimum detectable flux and emission line equivalent width in order to detect the faintest extragalactic emission line systems. In this way, OTELO data will complements other broad-band, narrow-band, and spectroscopic surveys. Methods . The red tunable filter of the OSIRIS instrument on the 10.4 m Gran Telescopio Canarias (GTC) is used to scan a spectral window centred at 9175 Å, which is free from strong sky emission lines, with a s ling interval of 6 Å and a bandwidth of 12 Å in the most deeply explored EGS region. Careful data reduction using improved techniques for sky ring subtraction, accurate astrometry, photometric calibration, and source extraction enables us to compile the OTELO catalogue. This catalogue is complemented with ancillary data ranging from deep X-ray to far-infrared, including high resolution HST images, which allow us to segregate the different types of targets, derive precise photometric redshifts, and obtain the morphological classification of the extragalactic objects detected. Results . The OTELO multi-wavelength catalogue contains 11 237 entries and is 50% complete at AB magnitude 26.38. Of these sources, 6600 have photometric redshifts with an uncertainty δ z phot better than 0.2 (1+ z phot ). A total of 4336 of these sources correspond to preliminary emission line candidates, which are complemented by 81 candidate stars and 483 sources that qualify as absorption line systems. The OTELO survey results will be released to the public on the second half of 2019.
Herschel ★ -ATLAS/GAMA: SDSS cross-correlation induced by weak lensing
Publisher: Oxford University Press (OUP)
Date: 26-06-2014
Identification of an [α/Fe]—Enhanced Thick Disk Component in an Edge-on Milky Way Analog
Publisher: American Astronomical Society
Date: 05-2021
Abstract: The Milky Way disk consists of two prominent components—a thick, alpha-rich, low-metallicity component and a thin, metal-rich, low-alpha component. External galaxies have been shown to contain thin- and thick-disk components, but whether distinct components in the [ α /Fe]–[Z/H] plane exist in other Milky Way-like galaxies is not yet known. We present Very Large Telescope (VLT)—Multi Unit Spectroscopic Explorer (MUSE) observations of UGC 10738, a nearby, edge-on Milky Way-like galaxy. We demonstrate through stellar population synthesis model fitting that UGC 10738 contains alpha-rich and alpha-poor stellar populations with similar spatial distributions to the same components in the Milky Way. We discuss how the finding that external galaxies also contain chemically distinct disk components may act as a significant constraint on the formation of the Milky Way’s own thin and thick disk.
The southern stellar stream spectroscopic survey (S5): Overview, target selection, data reduction, validation, and early science
Publisher: Oxford University Press (OUP)
Date: 03-10-2019
Abstract: We introduce the southern stellar stream spectroscopy survey (S5), an on-going program to map the kinematics and chemistry of stellar streams in the southern hemisphere. The initial focus of S5 has been spectroscopic observations of recently identified streams within the footprint of the dark energy survey (DES), with the eventual goal of surveying streams across the entire southern sky. Stellar streams are composed of material that has been tidally striped from dwarf galaxies and globular clusters and hence are excellent dynamical probes of the gravitational potential of the Milky Way, as well as providing a detailed snapshot of its accretion history. Observing with the 3.9 m Anglo-Australian Telescope’s 2-degree-Field fibre positioner and AAOmega spectrograph, and combining the precise photometry of DES DR1 with the superb proper motions from Gaia DR2, allows us to conduct an efficient spectroscopic survey to map these stellar streams. So far S5 has mapped nine DES streams and three streams outside of DES the former are the first spectroscopic observations of these recently discovered streams. In addition to the stream survey, we use spare fibres to undertake a Milky Way halo survey and a low-redshift galaxy survey. This paper presents an overview of the S5 program, describing the scientific motivation for the survey, target selection, observation strategy, data reduction, and survey validation. Finally, we describe early science results on stellar streams and Milky Way halo stars drawn from the survey. Updates on S5, including future public data releases, can be found at s5collab.github.io.
A RAVE investigation on Galactic open clusters: I. Radial velocities and metallicities
Publisher: EDP Sciences
Date: 02-2014
STELLAR POPULATION SYNTHESIS BASED MODELING of the MILKY WAY USING ASTEROSEISMOLOGY of 13,000 KEPLER RED GIANTS
Publisher: American Astronomical Society
Date: 27-04-2016
Galaxy And Mass Assembly (GAMA): bivariate functions of Hα star-forming galaxies
Publisher: Oxford University Press (OUP)
Date: 19-12-2014
The Smith Cloud and its dark matter halo: survival of a Galactic disc passage
Publisher: Oxford University Press (OUP)
Date: 26-06-2014
OAM interferometry: the detection of the rotational Doppler shift
Publisher: The Optical Society
Date: 22-08-2017
DOI: 10.1364/OE.25.021159
The Magellanic System: Stars, Gas, and Galaxies
Publisher: Cambridge University Press (CUP)
Date: 07-2008
DOI: 10.1017/S1743921308028913
Abstract: We provide a brief overview of some key issues that came out of the IAUS 256 symposium on the Magellanic System ( www.astro.keele.ac.uk/iaus256 ).
GASKAP-HI pilot survey science I: ASKAP zoom observations of Hi emission in the Small Magellanic Cloud
Publisher: Cambridge University Press (CUP)
Date: 2022
DOI: 10.1017/PASA.2021.59
Abstract: We present the most sensitive and detailed view of the neutral hydrogen ( ${\\rm H\\small I}$ ) emission associated with the Small Magellanic Cloud (SMC), through the combination of data from the Australian Square Kilometre Array Pathfinder (ASKAP) and Parkes (Murriyang), as part of the Galactic Australian Square Kilometre Array Pathfinder (GASKAP) pilot survey. These GASKAP-HI pilot observations, for the first time, reveal ${\\rm H\\small I}$ in the SMC on similar physical scales as other important tracers of the interstellar medium, such as molecular gas and dust. The resultant image cube possesses an rms noise level of 1.1 K ( $1.6\\,\\mathrm{mJy\\ beam}^{-1}$ ) $\\mathrm{per}\\ 0.98\\,\\mathrm{km\\ s}^{-1}$ spectral channel with an angular resolution of $30^{\\prime\\prime}$ ( ${\\sim}10\\,\\mathrm{pc}$ ). We discuss the calibration scheme and the custom imaging pipeline that utilises a joint deconvolution approach, efficiently distributed across a computing cluster, to accurately recover the emission extending across the entire ${\\sim}25\\,\\mathrm{deg}^2$ field-of-view. We provide an overview of the data products and characterise several aspects including the noise properties as a function of angular resolution and the represented spatial scales by deriving the global transfer function over the full spectral range. A preliminary spatial power spectrum analysis on in idual spectral channels reveals that the power law nature of the density distribution extends down to scales of 10 pc. We highlight the scientific potential of these data by comparing the properties of an outflowing high-velocity cloud with previous ASKAP+Parkes ${\\rm H\\small I}$ test observations.
Age patterns in a sample of spiral galaxies
Publisher: Oxford University Press (OUP)
Date: 03-06-2011
WARM IONIZED GAS REVEALED IN THE MAGELLANIC BRIDGE TIDAL REMNANT: CONSTRAINING THE BARYON CONTENT AND THE ESCAPING IONIZING PHOTONS AROUND DWARF GALAXIES
Publisher: American Astronomical Society
Date: 25-06-2013
THE STRUCTURE AND METALLICITY GRADIENT IN THE EXTREME OUTER DISK OF NGC 7793
Publisher: American Astronomical Society
Date: 07-04-2011
H-ATLAS/GAMA and HeViCS – dusty early-type galaxies in different environments
Publisher: Oxford University Press (OUP)
Date: 29-06-2015
Chemically Tagging the HR 1614 Moving Group
Publisher: American Astronomical Society
Date: 16-01-2007
DOI: 10.1086/510131
Fossil imprint of a powerful flare at the galactic center along the magellanic stream
Publisher: American Astronomical Society
Date: 06-11-2013
Laser Telemetry to Increase Astronomical Downlink Capacities
Publisher: IOP Publishing
Date: 06-2003
DOI: 10.1086/374915
Stellar populations – the next ten years
Publisher: Cambridge University Press (CUP)
Date: 12-2006
THE MAGELLANIC BRIDGE AS A DAMPED LYMAN ALPHA SYSTEM: PHYSICAL PROPERTIES OF COLD GAS TOWARD PKS 0312-770
Publisher: American Astronomical Society
Date: 07-04-2009
The vela cloud: A giant H i anomaly in the NGC 3256 group
Publisher: American Astronomical Society
Date: 08-12-2010
Lopsided galaxies: the case of NGC 891
Publisher: Oxford University Press (OUP)
Date: 08-2008
Galaxy And Mass Assembly: the 1.4 GHz SFR indicator, SFR–M*relation and predictions for ASKAP–GAMA
Publisher: Oxford University Press (OUP)
Date: 30-11-2016
A Search for Very Extended Ionized Gas in Nearby Starburst and Active Galaxies
Publisher: American Astronomical Society
Date: 11-2003
DOI: 10.1086/379000
Bright lights, Big city: Massive galaxies, giant Ly-a nebulae, and proto-clusters
Publisher: SPIE
Date: 02-2002
DOI: 10.1117/12.456509
Galaxy And Mass Assembly (GAMA): The mechanisms for quiescent galaxy formation at z < 1
Publisher: Oxford University Press (OUP)
Date: 02-10-2017
Probing the Southern Fermi Bubble in Ultraviolet Absorption Using Distant AGNs
Publisher: American Astronomical Society
Date: 15-06-2018
Mode-selective photonic lanterns for space-division multiplexing
Publisher: The Optical Society
Date: 10-01-2014
DOI: 10.1364/OE.22.001036
Galaxy and Mass Assembly (GAMA): the star formation rate dependence of the stellar initial mass function
Publisher: Oxford University Press (OUP)
Date: 04-07-2011
Improved distances and ages for stars common to TGAS and RAVE
Publisher: Oxford University Press (OUP)
Date: 21-04-2018
DOI: 10.1093/MNRAS/STY990
Potential applications of ring resonators for astronomical instrumentation
Publisher: IEEE
Date: 08-2011
The SAMI–Fornax Dwarfs Survey I: sample, observations, and the specific stellar angular momentum of dwarf elliptical galaxies
Publisher: Oxford University Press (OUP)
Date: 13-07-2020
Abstract: Dwarf ellipticals are the most common galaxy type in cluster environments however, the challenges associated with their observation mean that their formation mechanisms are still poorly understood. To address this, we present deep integral field observations of a s le of 31 low-mass (107.5 & M⋆ & 109.5 M⊙) early-type galaxies in the Fornax cluster with the SAMI instrument. For 21 galaxies, our observations are sufficiently deep to construct spatially resolved maps of the stellar velocity and velocity dispersion – for the remaining galaxies, we extract global velocities and dispersions from aperture spectra only. From the kinematic maps, we measure the specific stellar angular momentum λR of the lowest mass dE galaxies to date. Combining our observations with early-type galaxy data from the literature spanning a large range in stellar mass, we find that λR decreases towards lower stellar mass, with a corresponding increase in the proportion of slowly rotating galaxies in this regime. The decrease of λR with mass in our s le dE galaxies is consistent with a similar trend seen in somewhat more massive spiral galaxies from the CALIFA survey. This suggests that the degree of dynamical heating required to produce dEs from low-mass starforming progenitors may be relatively modest and consistent with a broad range of formation mechanisms.
Galaxy And Mass Assembly (GAMA): linking star formation histories and stellar mass growth
Publisher: Oxford University Press (OUP)
Date: 02-07-2013
GALAXY AND MASS ASSEMBLY (GAMA): MID-INFRARED PROPERTIES AND EMPIRICAL RELATIONS FROMWISE
Publisher: American Astronomical Society
Date: 31-01-2014
Galaxy and mass assembly (GAMA): projected galaxy clustering
Publisher: Oxford University Press (OUP)
Date: 13-10-2015
THE ABUNDANCE GRADIENT IN THE EXTREMELY FAINT OUTER DISK OF NGC 300
Publisher: American Astronomical Society
Date: 07-07-2021
Galaxy And Mass Assembly: resolving the role of environment in galaxy evolution
Publisher: Oxford University Press (OUP)
Date: 04-09-2013
Origins of the thick disk as traced by the alpha elements of metal-poor giant stars selected from RAVE
Publisher: American Astronomical Society
Date: 07-09-2010
Arbitrary on-chip optical filter using complex waveguide Bragg gratings
Publisher: AIP Publishing
Date: 07-03-2016
DOI: 10.1063/1.4943551
Abstract: We demonstrate a Complex Waveguide Bragg Grating (CWBG) which can be designed to generate an arbitrary transmission spectrum. A comprehensive design method, based on the Layer Peeling/Adding algorithm, is developed to realize the grating on a silica-on-silicon platform. The CWBG has a simple one-layer waveguide structure for ease of fabrication. A spectral precision better than ±0.1 nm and a suppression ratio between 15 dB and 33 dB are achieved for a transmission spectrum consisting of 20 randomly distributed spectral notches with a 3 dB width of 0.3–0.4 nm. Among the CWBG's various potential applications, we highlight its use for eliminating OH emission lines from the Earth's atmosphere for ground-based astronomical observations.
GAMA: towards a physical understanding of galaxy formation
Publisher: Oxford University Press (OUP)
Date: 10-2009
Star Formation in the Local Universe from the CALIFA Sample. II. Activation and Quenching Mechanisms in Bulges, Bars, and Disks
Publisher: American Astronomical Society
Date: 17-10-2019
Astrophophotonics: the next wave in observational cosmology
Publisher: IEEE
Date: 06-2009
The C iv linewidth distribution for quasars and its implications for broad-line region dynamics and virial mass estimation
Publisher: Oxford University Press (OUP)
Date: 03-11-2010
OVERVIEW OF THE SDSS-IV MaNGA SURVEY: MAPPING NEARBY GALAXIES AT APACHE POINT OBSERVATORY
Publisher: American Astronomical Society
Date: 10-12-2014
Measuring the Mass of the Large Magellanic Cloud with Stellar Streams Observed by S 5
Publisher: American Astronomical Society
Date: 12-2021
Abstract: Stellar streams are excellent probes of the underlying gravitational potential in which they evolve. In this work, we fit dynamical models to five streams in the Southern Galactic hemisphere, combining observations from the Southern Stellar Stream Spectroscopic Survey ( S 5 ), Gaia EDR3, and the Dark Energy Survey, to measure the mass of the Large Magellanic Cloud (LMC). With an ensemble of streams, we find a mass of the LMC ranging from ∼14–19 × 10 10 M ⊙ , probed over a range of closest approach times and distances. With the most constraining stream (Orphan–Chenab), we measure an LMC mass of 18.8 − 4.0 + 3.5 × 10 10 M ⊙ , probed at a closest approach time of 310 Myr and a closest approach distance of 25.4 kpc. This mass is compatible with previous measurements, showing that a consistent picture is emerging of the LMC’s influence on structures in the Milky Way. Using this s le of streams, we find that the LMC’s effect depends on the relative orientation of the stream and LMC at their point of closest approach. To better understand this, we present a simple model based on the impulse approximation and we show that the LMC’s effect depends both on the magnitude of the velocity kick imparted to the stream and the direction of this kick.
Star Clusters across Cosmic Time
Publisher: Annual Reviews
Date: 18-08-2019
DOI: 10.1146/ANNUREV-ASTRO-091918-104430
Abstract: Star clusters stand at the intersection of much of modern astrophysics: the ISM, gravitational dynamics, stellar evolution, and cosmology. Here, we review observations and theoretical models for the formation, evolution, and eventual disruption of star clusters. Current literature suggests a picture of this life cycle including the following several phases: ▪ Clusters form in hierarchically structured, accreting molecular clouds that convert gas into stars at a low rate per dynamical time until feedback disperses the gas. ▪ The densest parts of the hierarchy resist gas removal long enough to reach high star-formation efficiency, becoming dynamically relaxed and well mixed. These remain bound after gas removal. ▪ In the first ∼100 Myr after gas removal, clusters disperse moderately fast, through a combination of mass loss and tidal shocks by dense molecular structures in the star-forming environment. ▪ After ∼100 Myr, clusters lose mass via two-body relaxation and shocks by giant molecular clouds, processes that preferentially affect low-mass clusters and cause a turnover in the cluster mass function to appear on ∼1–10-Gyr timescales. ▪ Even after dispersal, some clusters remain coherent and thus detectable in chemical or action space for multiple galactic orbits. In the next decade, a new generation of space– and adaptive optics–assisted ground-based telescopes will enable us to test and refine this picture.
Mode-selective dissimilar fiber photonic-lantern spatial multiplexers for few-mode fiber
Publisher: Institution of Engineering and Technology
Date: 2013
DOI: 10.1049/CP.2013.1680
Exploring the dust content of galactic winds with Herschel – II. Nearby dwarf galaxies
Publisher: Oxford University Press (OUP)
Date: 13-03-2018
DOI: 10.1093/MNRAS/STY634
Wavelength-selective Switch for Few-mode Fiber Transmission
Publisher: Institution of Engineering and Technology
Date: 2013
DOI: 10.1049/CP.2013.1681
The SAMI pilot survey: The kinematic morphology-density relation in Abell 85, Abell 168 and Abell 2399
Publisher: Oxford University Press (OUP)
Date: 11-07-2014
The SAMI Pilot Survey: Stellar kinematics of galaxies in Abell 85, 168 and 2399
Publisher: Oxford University Press (OUP)
Date: 13-10-2015
Clustering of Lyα emitters around luminous quasars at z= 2-3: An alternative probe of reionization on galaxy formation
Publisher: Oxford University Press (OUP)
Date: 08-03-2012
Possibility of observable signatures of leptonium from astrophysical sources
Publisher: American Physical Society (APS)
Date: 03-06-2015
The GALAH survey: velocity fluctuations in the Milky Way using Red Clump giants
Publisher: Oxford University Press (OUP)
Date: 30-10-2019
The SAMI Galaxy Survey: Kinematic Alignments of Early-type Galaxies in A119 and A168
Publisher: American Astronomical Society
Date: 16-04-2019
Group quenching and galactic conformity at low redshift
Publisher: Oxford University Press (OUP)
Date: 22-03-2018
DOI: 10.1093/MNRAS/STY769
The Absence of Extratidal Structure in the Sculptor Dwarf Spheroidal Galaxy
Publisher: American Astronomical Society
Date: 09-2005
DOI: 10.1086/432662
Editorial: The LAMOST survey at the Guo Shou Jing Telescope
Publisher: IOP Publishing
Date: 27-06-2012
S 5: The Destruction of a Bright Dwarf Galaxy as Revealed by the Chemistry of the Indus Stellar Stream
Publisher: American Astronomical Society
Date: 07-2021
The GALAH survey: properties of the Galactic disc(s) in the solar neighbourhood
Publisher: Oxford University Press (OUP)
Date: 27-02-2018
DOI: 10.1093/MNRAS/STY525
THE CHEMICAL SIGNATURE OF A RELIC STAR CLUSTER IN THE SEXTANS DWARF SPHEROIDAL GALAXY—IMPLICATIONS FOR NEAR-FIELD COSMOLOGY
Publisher: American Astronomical Society
Date: 26-10-2012
The R-Process Alliance: Discovery of a Low-α, r-process-enhanced Metal-poor Star in the Galactic Halo
Publisher: American Astronomical Society
Date: 02-04-2019
The SAMI Galaxy Survey: Kinematics of Stars and Gas in Brightest Group Galaxies—The Role of Group Dynamics
Publisher: American Astronomical Society
Date: 02-2021
Abstract: We study the stellar and gas kinematics of the brightest group galaxies (BGGs) in dynamically relaxed and unrelaxed galaxy groups for a s le of 154 galaxies in the SAMI galaxy survey. We characterize the dynamical state of the groups using the luminosity gap between the two most luminous galaxies and the BGG offset from the luminosity centroid of the group. We find that the misalignment between the rotation axis of gas and stellar components is more frequent in the BGGs in unrelaxed groups, although with quite low statistical significance. Meanwhile, galaxies whose stellar dynamics would be classified as “regular rotators” based on their kinemetry are more common in relaxed groups. We confirm that this dependency on group dynamical state remains valid at fixed stellar mass and Sérsic index. The observed trend could potentially originate from a differing BGG accretion history in virialized and evolving groups. Among the halo relaxation probes, the group BGG offset appears to play a stronger role than the luminosity gap on the stellar kinematic differences of the BGGs. However, both the group BGG offset and luminosity gap appear to roughly equally drive the misalignment between the gas and stellar component of the BGGs in one direction. This study offers the first evidence that the dynamical state of galaxy groups may influence the BGG's stellar and gas kinematics, and we call for further studies using a larger s le with higher signal-to-noise.
Galaxy And Mass Assembly (GAMA): galaxy environments and star formation rate variations
Publisher: Oxford University Press (OUP)
Date: 06-06-2012
The SAMI Galaxy Survey: Detection of Environmental Dependence of Galaxy Spin in Observations and Simulations Using Marked Correlation Functions
Publisher: American Astronomical Society
Date: 09-2021
Evaluation of Photonic Lanterns for Lossless Mode-Multiplexing
Publisher: OSA
Date: 2012
THE RADIAL VELOCITY EXPERIMENT (RAVE): FIFTH DATA RELEASE
Publisher: American Astronomical Society
Date: 19-01-2017
Measuring the streaming motion in the Milky Way disc with Gaia EDR3+
Publisher: Oxford University Press (OUP)
Date: 23-01-2023
Abstract: We map the 3D kinematics of the Galactic disc out to 3.5 kpc from the Sun, and within 0.75 kpc from the mid-plane of the Galaxy. To this end, we combine high-quality astrometry from Gaia EDR3, with heliocentric line-of-sight velocities from Gaia DR2, and spectroscopic surveys including APOGEE, GALAH, and LAMOST. We construct an axisymmetric model for the mean velocity field, and subtract this on a star-by-star basis to obtain the residual velocity field in the Galactocentric components (Vϕ, VR, Vz), and Vlos. The velocity residuals are quantified using the power spectrum, and we find that the peak power (A/[km s−1]) in the mid-plane (|z| & 0.25 kpc) is (Aϕ, AR, AZ, Alos) = (4.2,8.5,2.6,4.6), at 0.25 & |z|/[kpc] & 0.5, is (Aϕ, AR, AZ, Alos) = (4.0,7.9,3.6,5.3), and at 0.5 & |z|/[kpc] & 0.75, is (Aϕ, AR, AZ, Alos) = (1.9,6.9,5.2,6.4). Our results provide a sophisticated measurement of the streaming motion in the disc and in the in idual components. We find that streaming is most significant in VR, and at all heights (|Z|) probed, but is also non-negligible in other components. Additionally, we find that patterns in velocity field overlap spatially with models for spiral arms in the Galaxy. Our simulations show that phase-mixing of disrupting spiral arms can generate such residuals in the velocity field, where the radial component is dominant, just as in real data. We also find that with time evolution, both the litude and physical scale of the residual motion decrease.
The SAMI Galaxy Survey: The Internal Orbital Structure and Mass Distribution of Passive Galaxies from Triaxial Orbit-superposition Schwarzschild Models
Publisher: American Astronomical Society
Date: 05-2022
Abstract: Dynamical models are crucial for uncovering the internal dynamics of galaxies however, most of the results to date assume axisymmetry, which is not representative of a significant fraction of massive galaxies. Here, we build triaxial Schwarzschild orbit-superposition models of galaxies taken from the SAMI Galaxy Survey, in order to reconstruct their inner orbital structure and mass distribution. The s le consists of 161 passive galaxies with total stellar masses in the range 10 9.5 –10 12 M ⊙ . We find that the changes in internal structures within 1 R e are correlated with the total stellar mass of the in idual galaxies. The majority of the galaxies in the s le (73% ± 3%) are oblate, while 19% ± 3% are mildly triaxial and 8% ± 2% have triaxial rolate shape. Galaxies with log M ⋆ / M ⊙ 10.50 are more likely to be non-oblate. We find a mean dark matter fraction of f DM = 0.28 ± 0.20, within 1 R e . Galaxies with higher intrinsic ellipticity (flatter) are found to have more negative velocity anisotropy β r (tangential anisotropy). β r also shows an anticorrelation with the edge-on spin parameter λ Re , EO , so that β r decreases with increasing λ Re , EO , reflecting the contribution from disk-like orbits in flat, fast-rotating galaxies. We see evidence of an increasing fraction of hot orbits with increasing stellar mass, while warm and cold orbits show a decreasing trend. We also find that galaxies with different ( V / σ – h 3 ) kinematic signatures have distinct combinations of orbits. These results are in agreement with a formation scenario in which slow- and fast-rotating galaxies form through two main channels.
Galaxy And Mass Assembly (GAMA): improved cosmic growth measurements using multiple tracers of large-scale structure
Publisher: Oxford University Press (OUP)
Date: 22-10-2013
Modeling the creep of polymer-based nanocomposites by using an alternative nonlinear optimization approach
Publisher: Springer Science and Business Media LLC
Date: 2013
Single-lined Spectroscopic Binary Star Candidates from a Combination of the RAVE and Gaia DR2 Surveys
Publisher: American Astronomical Society
Date: 23-09-2019
Imaging spectrophotometry of ionized gas in NGC 1068. II - Global ionization of the inner disk
Publisher: American Astronomical Society
Date: 07-1991
DOI: 10.1086/170170
Ultrafast laser inscription of a 121-waveguide fan-out for astrophotonics
Publisher: The Optical Society
Date: 08-06-2012
DOI: 10.1364/OL.37.002331
ULTRAFAINT DWARFS—STAR FORMATION AND CHEMICAL EVOLUTION IN THE SMALLEST GALAXIES
Publisher: American Astronomical Society
Date: 30-10-2014
DISCOVERY OF A GIANT, HIGHLY COLLIMATED JET FROM SANDULEAK'S STAR IN THE LARGE MAGELLANIC CLOUD
Publisher: American Astronomical Society
Date: 16-11-2011
Galaxy and Mass Assembly (GAMA): galaxies at the faint end of the Hα luminosity function
Publisher: Oxford University Press (OUP)
Date: 03-2011
Galaxy And Mass Assembly (GAMA) blended spectra catalogue: strong galaxy–galaxy lens and occulting galaxy pair candidates
Publisher: Oxford University Press (OUP)
Date: 04-2015
DOI: 10.1093/MNRAS/STV589
The GALAH survey: The data reduction pipeline
Publisher: Oxford University Press (OUP)
Date: 17-08-2017
High-resolution integrated photonic micro-spectrographs for radial velocity exoplanet astronomy
Publisher: IEEE
Date: 05-2013
Milky Way Tomography with the SkyMapper Southern Survey. II. Photometric Recalibration of SMSS DR2
Publisher: American Astronomical Society
Date: 29-01-2021
PRAXIS: An OH suppression optimised near infrared spectrograph
Publisher: SPIE
Date: 06-01-2020
DOI: 10.1117/12.2539883
Modelling kepler red giants in eclipsing binaries: Calibrating the mixing-length parameter with asteroseismology
Publisher: Oxford University Press (OUP)
Date: 08-12-2018
Distance determination for RAVE stars using stellar models: II. Most likely values assuming a standard stellar evolution scenario
Publisher: EDP Sciences
Date: 11-2010
Ultrabroadband High Coupling Efficiency Fiber-to-Waveguide Coupler Using Si$_{3}$N$_{4}$ /SiO$_{2}$ Waveguides on Silicon
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 10-2016
IONIZATION SOURCE OF A MINOR-AXIS CLOUD IN THE OUTER HALO OF M82
Publisher: American Astronomical Society
Date: 21-11-2012
Silicon Nitride/Silicon Dioxide Echelle Grating Spectrometer for Operation Near 1.55 μm
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 12-2018
The Millennium Galaxy Catalogue: on the natural subdivision of galaxies
Publisher: Oxford University Press (OUP)
Date: 10-10-2005
Thermal plasma in the giant lobes of the radio galaxy Centaurus A
Publisher: American Astronomical Society
Date: 04-02-2013
The GALAH Survey: using galactic archaeology to refine our knowledge of TESS target stars
Publisher: Oxford University Press (OUP)
Date: 16-04-2021
Abstract: An unprecedented number of exoplanets are being discovered by the Transiting Exoplanet Survey Satellite (TESS). Determining the orbital parameters of these exoplanets, and especially their mass and radius, will depend heavily upon the measured physical characteristics of their host stars. We have cross-matched spectroscopic, photometric, and astrometric data from GALAH Data Release 2, the TESS Input Catalog and Gaia Data Release 2, to create a curated, self-consistent catalogue of physical and chemical properties for 47 285 stars. Using these data, we have derived isochrone masses and radii that are precise to within 5 per cent. We have revised the parameters of three confirmed, and twelve candidate, TESS planetary systems. These results cast doubt on whether CTOI-20125677 is indeed a planetary system, since the revised planetary radii are now comparable to stellar sizes. Our GALAH–TESS catalogue contains abundances for up to 23 elements. We have specifically analysed the molar ratios for C/O, Mg/Si, Fe/Si, and Fe/Mg, to assist in determining the composition and structure of planets with Rp & 4R⊕. From these ratios, 36 per cent fall within 2$\\sigma$ sigma of the Sun/Earth values, suggesting that these stars may host rocky exoplanets with geological compositions similar to planets found within our own Solar system.
MMTF: THE MARYLAND-MAGELLAN TUNABLE FILTER
Publisher: American Astronomical Society
Date: 09-12-2009
The properties of the local spiral arms from RAVE data: two-dimensional density wave approach
Publisher: Oxford University Press (OUP)
Date: 29-08-2012
Galaxy Genesis — Unravelling the Epoch of Dissipation in the Early Disk
Publisher: Cambridge University Press (CUP)
Date: 2004
DOI: 10.1071/AS04030
Abstract: How did the Galactic disk form and can the sequence of events ever be unravelled from the vast stellar inventory? This will require that some of the residual inhomogeneities from prehistory escaped the dissipative process at an early stage. Fossil hunting to date has concentrated mostly on the stellar halo, but a key source of information will be the thick disk. This is believed to be a ‘snap frozen’ relic which formed during or shortly after the last major epoch of dissipation, or it may have formed from infalling systems early in the life of the Galaxy. As part of the KAOS Galaxy Genesis project, we explore the early history of the halo and the thick disk by looking for discrete substructures, either due to infall or in situ star formation, through chemical tagging. This will require high signal-to-noise echelle spectroscopy of up to a million stars throughout the disk. Our program has a short-term and a long-term goal. The short-term goal is to quantify the size and structure of the multi-dimensional chemical abundance space ( C -space) for all major components of the Galaxy. We seek to establish how many axes in ( C -space) are decoupled and have large intrinsic dispersions. A critical test of chemical tagging in the short term is that stellar streams in the halo, identified from detailed phase space information, are highly localised in ( C -space), or are confined to chemical tracks. These trajectories presuppose that stars form in a closed box through progressive enrichments of the gas, leading to stars dispersed along a narrow track in a complex chemical space. The long-term goal is to identify unique chemical signatures in the thick disk, originating from different formation sites, for star clusters which have long since dispersed. This will require precise chemical abundances for heavy elements such that a star can be localised to a discrete point in ( C -space). If the star clusters originally formed outside the Galaxy in a bound infalling system, the stellar abundances may fall along a chemical track, rather than a discrete point in ( C -space).
The SAMI Galaxy Survey: trends in [α/Fe] as a function of morphology and environment
Publisher: Oxford University Press (OUP)
Date: 12-2021
Abstract: We present a new set of index-based measurements of [α/Fe] for a s le of 2093 galaxies in the SAMI Galaxy Survey. Following earlier work, we fit a global relation between [α/Fe] and the galaxy velocity dispersion σ for red sequence galaxies, $[\\alpha /\\text{Fe}]=(0.378\\pm 0.009)\\rm {log}_{10}\\left(\\sigma /100\\right)+(0.155\\pm 0.003)$. We observe a correlation between the residuals and the local environmental surface density, whereas no such relation exists for blue cloud galaxies. In the full s le, we find that elliptical galaxies in high-density environments are α-enhanced by up to 0.057 ± 0.014 dex at velocity dispersions σ & 100 km s−1, compared with those in low-density environments. This α-enhancement is morphology-dependent, with the offset decreasing along the Hubble sequence towards spirals, which have an offset of 0.019 ± 0.014 dex. At low velocity dispersion and controlling for morphology, we estimate that star formation in high-density environments is truncated ∼1 Gyr earlier than in low-density environments. For elliptical galaxies only, we find support for a parabolic relationship between [α/Fe] and σ, with an environmental α-enhancement of at least 0.03 dex. This suggests strong contributions from both environment and mass-based quenching mechanisms. However, there is no evidence for this behaviour in later morphological types.
Precision radial velocities with inexpensive compact spectrographs
Publisher: SPIE
Date: 04-08-2016
DOI: 10.1117/12.2232126
The GALAH survey: stellar streams and how stellar velocity distributions vary with Galactic longitude, hemisphere, and metallicity
Publisher: Oxford University Press (OUP)
Date: 05-04-2018
DOI: 10.1093/MNRAS/STY865
Galaxy And Mass Assembly (GAMA): the galaxy luminosity function within the cosmic web
Publisher: Oxford University Press (OUP)
Date: 13-03-2015
DOI: 10.1093/MNRAS/STV237
Galaxy And Mass Assembly (GAMA): mass–size relations of z < 0.1 galaxies subdivided by Sérsic index, colour and morphology
Publisher: Oxford University Press (OUP)
Date: 10-01-2015
CALIFA, the Calar Alto Legacy Integral Field Area survey
Publisher: EDP Sciences
Date: 10-2016
Mapping the tilt of the Milky Way bulge velocity ellipsoids with ARGOS and Gaia DR2
Publisher: Oxford University Press (OUP)
Date: 14-01-2021
Abstract: Until the recent advent of Gaia Data Release 2 (DR2) and deep multi-object spectroscopy, it has been difficult to obtain 6D phase space information for large numbers of stars beyond 4 kpc, in particular towards the Galactic Centre, where dust and crowding are significant. We combine line-of-sight velocities from the Abundances and Radial velocity Galactic Origins Survey (ARGOS) with proper motions from Gaia DR2 to obtain a s le of ∼7000 red clump stars with 3D velocities. We perform a large-scale stellar kinematics study of the Milky Way bulge to characterize the bulge velocity ellipsoids in 20 fields. The tilt of the major-axis of the velocity ellipsoid in the radial-longitudinal velocity plane, or vertex deviation, is characteristic of non-axisymmetric systems and a significant tilt is a robust indicator of non-axisymmetry or bar presence. We compare the observations to the predicted kinematics of an N-body boxy-bulge model formed from dynamical instabilities. In the model, the lv values are strongly correlated with the angle (α) between the bulge major-axis and the Sun-Galactic centre line of sight. We use a maximum likelihood method to obtain an independent measurement of α, from bulge stellar kinematics alone, performing a robust error analysis. The most likely value of α given our model is α = (29 ± 3)○, with an additional systematic uncertainty due to comparison with one specific model. In Baade’s window, the metal-rich stars display a larger vertex deviation (lv = −40○) than the metal-poor stars (lv = 10○) but we do not detect significant lv−metallicity trends in the other fields.
The SAMI galaxy survey: gas velocity dispersions in low-z star-forming galaxies and the drivers of turbulence
Publisher: Oxford University Press (OUP)
Date: 20-05-2020
Abstract: We infer the intrinsic ionized gas kinematics for 383 star-forming galaxies across a range of integrated star formation rates (SFR ∈ [10−3, 102] M⊙ yr−1) at z ≲ 0.1 using a consistent 3D forward-modelling technique. The total s le is a combination of galaxies from the Sydney-AAO Multiobject Integral field Spectrograph (SAMI) Galaxy survey and DYnamics of Newly Assembled Massive Objects survey. For typical low-z galaxies taken from the SAMI Galaxy Survey, we find the vertical velocity dispersion (σv,z) to be positively correlated with measures of SFR, stellar mass, H i gas mass, and rotational velocity. The greatest correlation is with SFR surface density (ΣSFR). Using the total s le, we find σv,z increases slowly as a function of integrated SFR in the range SFR ∈ [10−3, 1] M⊙ yr−1 from 17 ± 3 to 24 ± 5 km s−1 followed by a steeper increase up to σv,z ∼80 km s−1 for SFR ≳ 1 M⊙ yr−1. This is consistent with recent theoretical models that suggest a σv,z floor driven by star formation feedback processes with an upturn in σv,z at higher SFR driven by gravitational transport of gas through the disc.
Double-lined spectroscopic binary stars in the rave survey
Publisher: American Astronomical Society
Date: 08-06-2010
Signature of a Massive Rotating Metal-poor Star Imprinted in the Phoenix Stellar Stream*
Publisher: American Astronomical Society
Date: 11-2021
The New Galaxy: Signatures of Its Formation
Publisher: Annual Reviews
Date: 09-2002
DOI: 10.1146/ANNUREV.ASTRO.40.060401.093840
Abstract: ▪ Abstract The formation and evolution of galaxies is one of the great outstanding problems of astrophysics. Within the broad context of hierachical structure formation, we have only a crude picture of how galaxies like our own came into existence. A detailed physical picture where in idual stellar populations can be associated with (tagged to) elements of the protocloud is far beyond our current understanding. Important clues have begun to emerge from both the Galaxy (near-field cosmology) and the high redshift universe (far-field cosmology). Here we focus on the fossil evidence provided by the Galaxy. Detailed studies of the Galaxy lie at the core of understanding the complex processes involved in baryon dissipation. This is a necessary first step toward achieving a successful theory of galaxy formation.
Galaxy And Mass Assembly (GAMA): trends in galaxy colours, morphology, and stellar populations with large-scale structure, group, and pair environments
Publisher: Oxford University Press (OUP)
Date: 19-06-2015
Correcting vortex splitting in higher order vortex beams
Publisher: The Optical Society
Date: 17-04-2014
DOI: 10.1364/OE.22.009920
Self-consistent Bulge/Disk/Halo Galaxy Dynamical Modeling Using Integral Field Kinematics
Publisher: American Astronomical Society
Date: 17-11-2017
Compact high-resolution spectrographs for large and extremely large telescopes: using the diffraction limit
Publisher: SPIE
Date: 05-10-2012
DOI: 10.1117/12.924937
Fundamental relations for the velocity dispersion of stars in the Milky Way
Publisher: Oxford University Press (OUP)
Date: 21-06-2021
Abstract: We explore the fundamental relations governing the radial and vertical velocity dispersions of stars in the Milky Way, from combined studies of complementary surveys including GALAH, LAMOST, APOGEE, the NASA Kepler and K2 missions, and Gaia DR2. We find that different stellar s les, even though they target different tracer populations and employ a variety of age estimation techniques, follow the same set of fundamental relations. We provide the clearest evidence to date that, in addition to the well-known dependence on stellar age, the velocity dispersions of stars depend on orbital angular momentum Lz, metallicity, and height above the plane |z|, and are well described by a multiplicatively separable functional form. The dispersions have a power-law dependence on age with exponents of 0.441 ± 0.007 and 0.251 ± 0.006 for σz and σR, respectively, and the power law is valid even for the oldest stars. For the solar neighbourhood stars, the apparent break in the power law for older stars, as seen in previous studies, is due to the anticorrelation of Lz with age. The dispersions decrease with increasing Lz until we reach the Sun’s orbital angular momentum, after which σz increases (implying flaring in the outer disc) while σR flattens. For a given age, the dispersions increase with decreasing metallicity, suggesting that the dispersions increase with birth radius. The dispersions also increase linearly with |z|. The same set of relations that work in the solar neighbourhood also work for stars between 3 & R/kpc & 20. Finally, the high-[α/Fe] stars follow the same relations as the low-[α/Fe] stars.
First science with SAMI: A serendipitously discovered galactic wind in ESO 185-G031
Publisher: American Astronomical Society
Date: 05-12-2012
Application of fiber tapers in astronomy
Publisher: SPIE
Date: 14-06-2006
DOI: 10.1117/12.673362
The 2dF-SDSS LRG and QSO (2SLAQ) Survey: thez< 2.1 quasar luminosity function from 5645 quasars tog= 21.85
Publisher: Oxford University Press (OUP)
Date: 07-2005
The SAMI Galaxy Survey: Quenching of Star Formation in Clusters I. Transition Galaxies
Publisher: American Astronomical Society
Date: 04-03-2019
Warm ionized gas in CALIFA early-type galaxies
Publisher: EDP Sciences
Date: 21-03-2016
Void asymmetries in the cosmic web: A mechanism for bulk flows
Publisher: Cambridge University Press (CUP)
Date: 06-2014
DOI: 10.1017/S1743921316010589
Abstract: Bulk flows of galaxies moving with respect to the cosmic microwave background are well established observationally and seen in the most recent ΛCDM simulations. With the aid of an idealised Gadget-2 simulation, we show that void asymmetries in the cosmic web can exacerbate local bulk flows of galaxies. The {\\it Cosmicflows-2} survey, which has mapped in detail the 3D structure of the Local Universe, reveals that the Local Group resides in a “local sheet” of galaxies that borders a “local void” with a diameter of about 40 Mpc. The void is emptying out at a rate of 16 km s -1 Mpc -1 . In a co-moving frame, the Local Sheet is found to be moving away from the Local Void at ∼ 260 km s -1 . Our model shows how asymmetric collapse due to unbalanced voids on either side of a developing sheet or wall can lead to a systematic movement of the sheet. We conjectured that asymmetries could lead to a large-scale separation of dark matter and baryons, thereby driving a dependence of galaxy properties with environment, but we do {\\it not} find any evidence for this effect.
The SAMI Galaxy Survey: spatially resolving the environmental quenching of star formation in GAMA galaxies
Publisher: Oxford University Press (OUP)
Date: 12-09-2017
Characterizing the high-velocity stars of RAVE: The discovery of a metal-rich halo star born in the Galactic disc
Publisher: Oxford University Press (OUP)
Date: 03-01-2015
Broken into Pieces: ATLAS and Aliqa Uma as One Single Stream
Publisher: American Astronomical Society
Date: 04-2021
Abstract: We present the first spectroscopic measurements of the ATLAS and Aliqa Uma streams from the Southern Stellar Stream Spectroscopic Survey ( S 5 ), in combination with the photometric data from the Dark Energy Survey and astrometric data from Gaia. From the coherence of spectroscopic members in radial velocity and proper motion, we find that these two systems are extremely likely to be one stream with discontinuity in morphology and density on the sky (the “kink” feature). We refer to this entire stream as the ATLAS-Aliqa Uma stream, or the AAU stream. We perform a comprehensive exploration of the effect of baryonic substructures and find that only an encounter with the Sagittarius dwarf ∼0.5 Gyr ago can create a feature similar to the observed “kink.” In addition, we also identify two gaps in the ATLAS component associated with the broadening in the stream width (the “broadening” feature). These gaps have likely been created by small mass perturbers, such as dark matter halos, as the AAU stream is the most distant cold stream known with severe variations in both the stream surface density and the stream track on the sky. With the stream track, stream distance, and kinematic information, we determine the orbit of the AAU stream and find that it has been affected by the Large Magellanic Cloud, resulting in a misalignment between the proper motion and stream track. Together with the Orphan-Chenab Stream, AAU is the second stream pair that has been found to be a single stream separated into two segments by external perturbation.
The Source of Ionization along the Magellanic Stream
Publisher: American Astronomical Society
Date: 02-11-2007
DOI: 10.1086/524657
Galaxy And Mass Assembly (GAMA): spectroscopic analysis
Publisher: Oxford University Press (OUP)
Date: 07-02-2013
DOI: 10.1093/MNRAS/STT030
First starlight spectrum captured using an integrated photonic micro-spectrograph
Publisher: EDP Sciences
Date: 20-07-2012
Exploring the dust content of galactic haloes with Herschel III. NGC 891
Publisher: Oxford University Press (OUP)
Date: 18-11-2020
Abstract: We present deep far-infrared observations of the nearby edge-on galaxy NGC 891 obtained with the Herschel Space Observatory and the Spitzer Space Telescope. The maps confirm the detection of thermal emission from the inner circumgalactic medium (halo) and spatially resolve a dusty superbubble and a dust spur (filament). The dust temperature of the halo component is lower than that of the disc but increases across a region of diameter ≈8.0 kpc extending at least 7.7 kpc vertically from one side of the disc, a region we call a superbubble because of its association with thermal X-ray emission and a minimum in the synchrotron scale height. This outflow is breaking through the thick disc and developing into a galactic wind, which is of particular interest because NGC 891 is not considered a starburst galaxy the star formation rate surface density, 0.03 M⊙ yr−1 kpc−2, and gas fraction, just $10{{\\ \\rm per\\ cent}}$ in the inner disc, indicate the threshold for wind formation is lower than previous work has suggested. We conclude that the star formation surface density is sufficient for superbubble blowout into the halo, but the cosmic ray electrons may play a critical role in determining whether this outflow develops into a fountain or escapes from the gravitational potential. The high dust-to-gas ratio in the dust spur suggests the material was pulled out of NGC 891 through the collision of a minihalo with the disc of NGC 891. We conclude that NGC 891 offers an ex le of both feedback and satellite interactions transporting dust into the halo of a typical galaxy.
Quantum memories and the double-slit experiment: implications for astronomical interferometry
Publisher: Optica Publishing Group
Date: 30-06-2021
DOI: 10.1364/JOSAB.424651
Abstract: Thomas Young’s slit experiment lies at the heart of classical interference and quantum mechanics. Over the last 50 years, it has been shown that particles (e.g., photons, electrons, large molecules), even in idual particles, generate an interference pattern at a distant screen after passage through a double slit, thereby demonstrating wave-particle duality. We revisit this famous experiment by replacing both slits with single-mode fiber inputs to two independent quantum memories that are capable of storing the incident electromagnetic field’s litude and phase as a function of time. At a later time, the action is reversed: the quantum memories are read out in synchrony, and the single-mode fiber outputs are allowed to interact, consistent with the original observation. In contrast to any classical memory device, the write and read processes of a quantum memory are non-destructive and hence preserve the photonic quantum states. In principle, with sufficiently long storage times and sufficiently high photonic storage capacity, quantum memories operating at widely separated telescopes can be brought together to achieve optical interferometry over arbitrarily long baselines.
Two-dimensional multi-component photometric decomposition of CALIFA galaxies
Publisher: EDP Sciences
Date: 27-01-2017
Abundances in the Milky Way across Five Nucleosynthetic Channels from 4 Million LAMOST Stars
Publisher: American Astronomical Society
Date: 23-07-2020
Galaxy And Mass Assembly (GAMA): estimating galaxy group masses via caustic analysis
Publisher: Oxford University Press (OUP)
Date: 07-05-2012
Galaxy And Mass Assembly (GAMA): the life and times of L★ galaxies
Publisher: Oxford University Press (OUP)
Date: 08-03-2013
DOI: 10.1093/MNRAS/STT156
Galaxy And Mass Assembly (GAMA): the absence of stellar mass segregation in galaxy groups and consistent predictions from GALFORM and EAGLE simulations
Publisher: Oxford University Press (OUP)
Date: 12-09-2016
Deep sky surveys: A motivation for stacking digitized photographic plates
Publisher: American Astronomical Society
Date: 11-1993
DOI: 10.1086/116792
The GALAH Survey: improving our understanding of confirmed and candidate planetary systems with large stellar surveys
Publisher: Oxford University Press (OUP)
Date: 02-12-2021
Abstract: Pioneering photometric, astrometric, and spectroscopic surveys is helping exoplanetary scientists better constrain the fundamental properties of stars within our galaxy and the planets these stars host. In this study, we use the third data release from the stellar spectroscopic GALAH Survey, coupled with astrometric data of eDR3 from the Gaia satellite, and other data from NASA’s Exoplanet Archive, to refine our understanding of 279 confirmed and candidate exoplanet host stars and their exoplanets. This homogenously analysed data set comprises 105 confirmed exoplanets, along with 146 K2 candidates, 95 TESS Objects of Interest (TOIs), and 52 Community TOIs (CTOIs). Our analysis significantly shifts several previously (unknown) planet parameters while decreasing the uncertainties for others. Our radius estimates suggest that 35 planet candidates are more likely brown dwarfs or stellar companions due to their new radius values. We are able to refine the radii and masses of WASP-47 e, K2-106 b, and CoRoT-7 b to their most precise values yet to less than 2.3 per cent and 8.5 per cent, respectively. We also use stellar rotational values from GALAH to show that most planet candidates will have mass measurements that will be tough to obtain with current ground-based spectrographs. With GALAH’s chemical abundances, we show through chemo-kinematics that there are five planet hosts that are associated with the galaxy’s thick disc, including NGTS-4, K2-183, and K2-337. Finally, we show that there is no statistical difference between the chemical properties of hot Neptune and hot rocky exoplanet hosts, with the possibility that short-period rocky worlds might be the remnant cores of hotter, gaseous worlds.
Diffuse Stellar Light at 100 Kiloparsec Scales in M87
Publisher: American Astronomical Society
Date: 12-1997
DOI: 10.1086/304886
Efficient multi-mode to single-mode conversion in a 61 port photonic lantern
Publisher: SPIE
Date: 11-02-2010
DOI: 10.1117/12.841736
2023 Astrophotonics Roadmap: pathways to realizing multi-functional integrated astrophotonic instruments
Publisher: IOP Publishing
Date: 10-2023
Abstract: Photonic technologies offer numerous functionalities that can be used to realize astrophotonic instruments. The most spectacular ex le to date is the ESO Gravity instrument at the Very Large Telescope in Chile that combines the light-gathering power of four 8-m telescopes through a complex photonic interferometer. Fully integrated astrophotonic devices offer critical advantages for instrument development, including extreme miniaturization when operating at the diffraction-limit, plus integration, superior thermal and mechanical stabilization owing to the small footprint, and high replicability offering significant cost savings. Numerous astrophotonic technologies have been developed to address shortcomings of conventional instruments to date, including the development of photonic lanterns to convert from multimode inputs to single mode outputs, complex aperiodic fiber Bragg gratings to filter OH emission from the atmosphere, beam combiners enabling long baseline interferometry with for ex le, ESO Gravity, and laser frequency combs for high precision spectral calibration of spectrometers. Despite these successes, the facility implementation of photonic solutions in astronomical instrumentation is currently limited because of 1) low throughputs from coupling to fibers, coupling fibers to chips, propagation and bend losses, device losses, etc., 2) difficulties with scaling to large channel count devices needed for large bandwidths and high resolutions, and 3) efficient integration of photonics with detectors. In this roadmap, we identify 23 key areas that need further development. We outline the challenges and advances needed across those areas covering design tools, simulation capabilities, fabrication processes, the need for entirely new components, integration and hybridization and the characterization of devices. To realize these advances the astrophotonics community will have to work cooperatively with industrial partners who have more advanced manufacturing capabilities. With the advances described herein, multi-functional integrated instruments will be realized leading to novel observing capabilities for both ground and space based platforms, enabling new scientific studies and discoveries.
GALAXY AND MASS ASSEMBLY (GAMA): WITNESSING THE ASSEMBLY OF THE CLUSTER ABELL 1882
Publisher: American Astronomical Society
Date: 11-07-2013
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