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Astronomical and Space Sciences | Cosmology and Extragalactic Astronomy | Stellar Astronomy and Planetary Systems | Astronomical and Space Instrumentation
Expanding Knowledge in the Physical Sciences | Expanding Knowledge in Technology |
Publisher: Oxford University Press (OUP)
Date: 12-11-2023
Abstract: The WALLABY pilot survey has been conducted using the Australian SKA Pathfinder (ASKAP). The integrated 21-cm H i line spectra are formed in a very different manner compared to usual single-dish spectra Tully–Fisher measurements. It is thus extremely important to ensure that slight differences (e.g. biases due to missing flux) are quantified and understood in order to maximise the use of the large amount of data becoming available soon. This article is based on four fields for which the data are scientifically interesting by themselves. The pilot data discussed here consist of 614 galaxy spectra at a rest wavelength of 21 cm. Of these spectra, 472 are of high enough quality to be used to potentially derive distances using the Tully–Fisher relation. We further restrict the s le to the 251 galaxies whose inclination is sufficiently close to edge-on. For these, we derive Tully–Fisher distances using the deprojected WALLABY velocity widths combined with infrared (WISE W1) magnitudes. The resulting Tully–Fisher distances for the Eridanus, Hydra, Norma, and NGC4636 clusters are 21.5, 53.5, 69.4, and 23.0 Mpc, respectively, with uncertainties of 5–10 per cent, which are better or equivalent to the ones obtained in studies using data obtained with giant single dish telescopes. The pilot survey data show the benefits of WALLABY over previous giant single-dish telescope surveys. WALLABY is expected to detect around half a million galaxies with a mean redshift of $z = 0.05 (200\\, \\mathrm{Mpc})$. This study suggests that about 200 000 Tully–Fisher distances might result from the survey.
Publisher: Oxford University Press (OUP)
Date: 08-03-2017
DOI: 10.1093/MNRAS/STX562
Publisher: Oxford University Press (OUP)
Date: 20-11-2017
Publisher: EDP Sciences
Date: 31-10-2012
Publisher: Oxford University Press (OUP)
Date: 06-04-2022
Abstract: We construct the halo mass function (HMF) from the GAMA (Galaxy And Mass Assembly) galaxy group catalogue over the mass range of 1012.7–1015.5 M⊙, and find good agreement with the expectation from Lambda cold dark matter. In comparison to previous studies, this result extends the mass range over which the HMF has now been measured over by an order of magnitude. We combine the GAMA data release (DR) 4 HMF with similar data from the Sloan Digital Sky Survey (SDSS) DR12 and REFLEX II (ROSAT-ESO Flux Limited X-ray Galaxy Cluster Survey) surveys, and fit a four-parameter Murray–Robotham–Power function, valid at $\\tilde{z} \\approx 0.1$, yielding a density normalization of log10 (ϕ* Mpc$^{3})= -3.96^{+0.55}_{-0.82}$, a high mass turnover of log10 (M* M$_{\\odot }^{-1})=14.13^{+0.43}_{-0.40}$, a low-mass power-law slope of $\\alpha =-1.68^{+0.21}_{-0.24}$, and a high-mass softening parameter of $\\beta =0.63^{+0.25}_{-0.11}$. If we fold in the constraint on ΩM from the Planck 2018 cosmology, we are able to reduce these uncertainties further, but this relies on the assumption that the power-law trend can be extrapolated from 1012.7 M⊙ to zero mass. Throughout, we highlight the effort needed to improve on our HMF measurement: improved halo mass estimates that do not rely on calibration to simulations reduced halo mass uncertainties needed to mitigate the strong Eddington bias that arises from the steepness of the HMF low-mass slope and deeper wider area spectroscopic surveys. To our halo mass limit of 1012.7 M⊙, we are directly resolving (‘seeing’) 41 ± 5 per cent of the total mass density, i.e. ΩM,& .7 = 0.128 ± 0.016, opening the door for the direct construction of three-dimensional dark matter mass maps at Mpc resolution.
Publisher: Oxford University Press (OUP)
Date: 17-11-2017
Publisher: Oxford University Press (OUP)
Date: 11-06-2015
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.
Publisher: Oxford University Press (OUP)
Date: 19-12-2019
Abstract: We use data from the GAMA and GALEX surveys to demonstrate that the UV upturn, an unexpected excess of ultraviolet flux from a hot stellar component, seen in the spectra of many early-type galaxies, arises from processes internal to in idual galaxies with no measurable influence from the galaxies’ larger environment. We first define a clean s le of passive galaxies without a significant contribution to their UV flux from low-level star formation. We confirm that galaxies with the optical colours of red sequence galaxies often have signs of residual star formation, which, without other information, would prevent a convincing demonstration of the presence of UV upturns. However, by including (NUV−u) and WISE (W2–W3) colours, and FUV data where it exists, we can convincingly constrain s les to be composed of non-star-forming objects. Using such a s le, we examine GALEX photometry of low-redshift GAMA galaxies in a range of low-density environments, from groups to the general field, searching for UV upturns. We find a wide range of (NUV−r) colours, entirely consistent with the range seen – and attributed to the UV upturn – in low-redshift red sequence cluster galaxies. The range of colours is independent of group multiplicity or velocity dispersion, with isolated passive galaxies just as likely to have blue UV-to-optical colours, implying significant upturn components, as those in richer groups and in the previous data on clusters. This is supported by equivalent results for (FUV−r) colours which are clear indicators of upturn components.
Publisher: Oxford University Press (OUP)
Date: 18-11-2011
Publisher: Oxford University Press (OUP)
Date: 27-06-2011
Publisher: Oxford University Press (OUP)
Date: 14-04-2018
DOI: 10.1093/MNRAS/STY933
Publisher: Oxford University Press (OUP)
Date: 11-12-2016
Publisher: American Astronomical Society
Date: 07-03-2013
Publisher: Oxford University Press (OUP)
Date: 03-2012
Publisher: Oxford University Press (OUP)
Date: 18-08-2022
Abstract: We derive single Sérsic fits and bulge-disc decompositions for 13 096 galaxies at redshifts z & 0.08 in the GAMA II equatorial survey regions in the Kilo-Degree Survey (KiDS) g, r, and i bands. The surface brightness fitting is performed using the Bayesian two-dimensional profile fitting code ProFit. We fit three models to each galaxy in each band independently with a fully automated Markov chain Monte Carlo analysis: a single Sérsic model, a Sérsic plus exponential and a point source plus exponential. After fitting the galaxies, we perform model selection and flag galaxies for which none of our models are appropriate (mainly mergers/Irregular galaxies). The fit quality is assessed by visual inspections, comparison to previous works, comparison of independent fits of galaxies in the overlap regions between KiDS tiles and bespoke simulations. The latter two are also used for a detailed investigation of systematic error sources. We find that our fit results are robust across various galaxy types and image qualities with minimal biases. Errors given by the MCMC underestimate the true errors typically by factors 2–3. Automated model selection criteria are accurate to $\\gt 90{{\\ \\rm per\\ cent}}$ as calibrated by visual inspection of a subs le of galaxies. We also present g−r component colours and the corresponding colour–magnitude diagram, consistent with previous works despite our increased fit flexibility. Such reliable structural parameters for the components of a erse s le of galaxies across multiple bands will be integral to various studies of galaxy properties and evolution. All results are integrated into the GAMA database.
Publisher: Oxford University Press (OUP)
Date: 20-06-2016
Publisher: Oxford University Press (OUP)
Date: 13-01-2015
Publisher: Oxford University Press (OUP)
Date: 19-12-2014
Publisher: Oxford University Press (OUP)
Date: 29-06-2013
DOI: 10.1093/MNRAS/STT890
Publisher: American Astronomical Society
Date: 04-2023
Abstract: We derive new empirical scaling relations between Wide-field Infrared Survey Explorer (WISE) mid-IR (MIR) galaxy photometry and well-determined stellar masses from spectral energy distribution modeling of a suite of optical–infrared photometry provided by the Data Release 4 (DR4) Catalog of the GAMA-KiDS-VIKING survey of the southern G23 field. The MIR source extraction and characterization are drawn from the WISE Extended Source Catalogue and the archival ALLWISE catalog, combining both resolved and compact galaxies in the G23 s le to a redshift of 0.15. Three scaling relations are derived: W1 3.4 μ m luminosity versus stellar mass, and WISE W1–W2, W1–W3 colors versus mass-to-light ratio ( M / L , sensitive to a variety of galaxy types from passive to star-forming). For each galaxy in the s le, we then derive the combined stellar mass from these scaling relations, producing M ⋆ estimates with better than ∼25%–30% accuracy for galaxies with 9 M ⊙ and %–50% for lower-luminosity dwarf galaxies. We also provide simple prescriptions for rest-frame corrections and estimating stellar masses using only the W1 flux and the W1–W2 color, making stellar masses more accessible to users of the WISE data. Given a redshift or distance, these new scaling relations will enable stellar mass estimates for any galaxy in the sky detected by WISE with high fidelity across a range of M / L ratios.
Publisher: Oxford University Press (OUP)
Date: 03-06-2020
Abstract: The Galaxy And Mass Assembly Survey (GAMA) covers five fields with highly complete spectroscopic coverage (& per cent) to intermediate depths (r & 19.8 or i & 19.0 mag), and collectively spans 250 deg2 of equatorial or southern sky. Four of the GAMA fields (G09, G12, G15, and G23) reside in the European Southern Observatory (ESO) VST KiDS and ESO VISTA VIKING survey footprints, which combined with our GALEX, WISE, and Herschel data provide deep uniform imaging in the $FUV/NUV/u/g/r/i/Z/Y/J/H/K_s/W1/W2/W3/W4/P100/P160/S250/S350/S500$ bands. Following the release of KiDS DR4, we describe the process by which we ingest the KiDS data into GAMA (replacing the SDSS data previously used for G09, G12, and G15), and redefine our core optical and near-infrared (NIR) catalogues to provide a complete and homogeneous data set. The source extraction and analysis is based on the new ProFound image analysis package, providing matched-segment photometry across all bands. The data are classified into stars, galaxies, artefacts, and ambiguous objects, and objects are linked to the GAMA spectroscopic target catalogue. Additionally, a new technique is employed utilizing ProFound to extract photometry in the unresolved MIR–FIR regime. The catalogues including the full FUV–FIR photometry are described and will be fully available as part of GAMA DR4. They are intended for both standalone science, selection for targeted follow-up with 4MOST, as well as an accompaniment to the upcoming and ongoing radio arrays now studying the GAMA 23h field.
Publisher: Oxford University Press (OUP)
Date: 24-11-2017
Publisher: American Astronomical Society
Date: 13-07-2016
Publisher: American Astronomical Society
Date: 16-04-2018
Publisher: American Astronomical Society
Date: 20-07-2020
Publisher: Oxford University Press (OUP)
Date: 03-08-2012
Publisher: Oxford University Press (OUP)
Date: 12-12-2011
Publisher: Oxford University Press (OUP)
Date: 02-10-2017
Publisher: American Astronomical Society
Date: 04-2022
Abstract: Understanding the connection between nuclear activity and galaxy environment remains critical in constraining models of galaxy evolution. By exploiting the extensive cataloged data from the Galaxy and Mass Assembly survey, we identify a representative s le of 205 quasars at 0.1 z 0.35 and establish a comparison s le of galaxies, closely matched to the quasar s le in terms of both stellar mass and redshift. On scales Mpc, the galaxy number counts and group membership of quasars appear entirely consistent with those of the matched galaxy s le. Despite this, we find that quasars are ∼1.5 times more likely to be classified as the group center, indicating a potential link between quasar activity and cold gas flows or galaxy interactions associated with rich group environments. On scales of ∼a few Mpc, the clustering strengths of both s les are statistically consistent, and beyond 10 Mpc, we find no evidence that quasars trace large-scale structures any more than the galaxy control s le. Both populations are found to prefer intermediate-density sheets and filaments to either very high-density environments or very low-density environments. This weak dependence of quasar activity on galaxy environment supports a paradigm in which quasars represent a phase in the lifetime of all massive galaxies and in which secular processes and a group-centric location are the dominant triggers of quasars at low redshift.
Publisher: Oxford University Press (OUP)
Date: 04-07-2011
Publisher: Oxford University Press (OUP)
Date: 11-04-2022
Abstract: We present the Australian Square Kilometre Array Pathfinder (ASKAP) observations of the Galaxy and Mass Assembly (GAMA)-23h field. The survey was carried out at 887.5 MHz and covers an ∼83 square deg field. We imaged the calibrated visibility data, taken as part of the Evolutionary Mapping of Universe Early Science Programme, using the latest version of the ASKAPSoft pipeline. The final mosaic has an angular resolution of 10 arcsec and a central rms noise of around 38 $\\mu$Jy beam−1. The derived radio source catalogue has 39 812 entries above a peak flux density threshold of 5σ. We searched for the radio source host galaxy counterparts using the GAMA spectroscopic (with an i-band magnitude limit of 19.2 mag) and multiwavelength catalogues that are available as part of the collaboration. We identified hosts with GAMA spectroscopic redshifts for 5934 radio sources. We describe the data reduction, imaging, and source identification process, and present the source counts. Thanks to the wide area covered by our survey, we obtain very robust counts down to 0.2 mJy. ASKAP’s exceptional survey speed, providing efficient, sensitive, and high-resolution mapping of large regions of the sky in conjunction with the multiwavelength data available for the GAMA23 field, allowed us to discover 63 giant radio galaxies. The data presented here demonstrate the excellent capabilities of ASKAP in the pre-SKA era.
Publisher: Oxford University Press (OUP)
Date: 02-07-2013
Publisher: Oxford University Press (OUP)
Date: 05-08-2020
Abstract: Large multiobject spectroscopic surveys require automated algorithms to optimize their observing strategy. One of the most ambitious upcoming spectroscopic surveys is the 4MOST survey. The 4MOST survey facility is a fibre-fed spectroscopic instrument on the VISTA telescope with a large enough field of view to survey a large fraction of the southern sky within a few years. Several Galactic and extragalactic surveys will be carried out simultaneously, so the combined target density will strongly vary. In this paper, we describe a new tiling algorithm that can naturally deal with the large target density variations on the sky and which automatically handles the different exposure times of targets. The tiling pattern is modelled as a marked point process, which is characterized by a probability density that integrates the requirements imposed by the 4MOST survey. The optimal tilling pattern with respect to the defined model is estimated by the tiles configuration that maximizes the proposed probability density. In order to achieve this maximization a simulated annealing algorithm is implemented. The algorithm automatically finds an optimal tiling pattern and assigns a tentative sky brightness condition and exposure time for each tile, while minimizing the total execution time that is needed to observe the list of targets in the combined input catalogue of all surveys. Hence, the algorithm maximizes the long-term observing efficiency and provides an optimal tiling solution for the survey. While designed for the 4MOST survey, the algorithm is flexible and can with simple modifications be applied to any other multiobject spectroscopic survey.
Publisher: Springer Science and Business Media LLC
Date: 17-09-2019
DOI: 10.1038/S41467-019-12242-1
Abstract: Studies of rodent models of Alzheimer’s disease (AD) and of human tissues suggest that the retinal changes that occur in AD, including the accumulation of amyloid beta (Aβ), may serve as surrogate markers of brain Aβ levels. As Aβ has a wavelength-dependent effect on light scatter, we investigate the potential for in vivo retinal hyperspectral imaging to serve as a biomarker of brain Aβ. Significant differences in the retinal reflectance spectra are found between in iduals with high Aβ burden on brain PET imaging and mild cognitive impairment ( n = 15), and age-matched PET-negative controls ( n = 20). Retinal imaging scores are correlated with brain Aβ loads. The findings are validated in an independent cohort, using a second hyperspectral camera. A similar spectral difference is found between control and 5xFAD transgenic mice that accumulate Aβ in the brain and retina. These findings indicate that retinal hyperspectral imaging may predict brain Aβ load.
Publisher: American Astronomical Society
Date: 31-01-2014
Publisher: American Astronomical Society
Date: 17-02-2017
Publisher: American Astronomical Society
Date: 14-02-2017
Publisher: Oxford University Press (OUP)
Date: 26-04-2023
Abstract: We develop a framework for using clustering-based redshift inference (cluster-$z$ ) to measure the evolving galaxy luminosity function (GLF) and galaxy stellar mass function (GSMF) using Wide-field Infrared Survey Explorer W1 (3.4 μm) mid-infrared photometry and positions. We use multiple reference sets from the Galaxy And Mass Assembly survey, Sloan Digital Sky Survey and Baryon Oscillation Spectroscopic Survey. Combining the resulting cluster-$z$ s allows us to enlarge the study area, and by accounting for the specific properties of each reference set, making best use of each reference set to produce the best overall result. Thus we are able to measure the GLF and GSMF over ∼7500 deg2 of the Northern Galactic Cap up to $z$ & 0.6. Our method can easily be adapted for new studies with fainter magnitudes, which pose difficulties for the derivation of photo-$z$ s. With better statistics in future surveys this technique is a strong candidate for studies with new emerging data from, e.g. the Vera C Rubin Observatory, the Euclid mission or the Nancy Grace Roman Space Telescope.
Publisher: Oxford University Press (OUP)
Date: 04-09-2013
Publisher: Oxford University Press (OUP)
Date: 03-12-2015
Publisher: Cambridge University Press (CUP)
Date: 09-2011
DOI: 10.1017/S1743921312009404
Abstract: Present and past gas-fuelling of galaxies is expected to depend upon both the properties of the galaxies themselves, as well as their larger-scale environments. In the case of galaxies in groups the environment, i.e the group mass, can be probed by measuring the velocity dispersion of the group members, as done with the GAMA Galaxy Group catalogue (Robotham et al . 2011), probing the halo mass function all the way to small groups. The gas-fuelling rate of normal late-type galaxies can be traced by the SFR under the assumption of a steady state between gas-fuelling and gas-consumption by SF. We present a method to estimate disk opacities from UV/optical photometric characteristics, calibrated using the radiative transfer model of Popescu et al . (2011), applied to UV-Opt-FIR GAMA/H-ATLAS photometry for a subset of GAMA galaxies. We use the method to extract attenuation corrected SFRs for a large s le of late-type GAMA galaxies, which we use in an initial application to constrain the dependency of star formation/gas-fuelling in late-type galaxies on mass of parent DMH, and compactness of galaxy group.
Publisher: EDP Sciences
Date: 28-04-2016
Publisher: Oxford University Press (OUP)
Date: 11-12-2017
Publisher: Oxford University Press (OUP)
Date: 22-01-2018
DOI: 10.1093/MNRAS/STY124
Publisher: EDP Sciences
Date: 06-11-2008
Publisher: Oxford University Press (OUP)
Date: 18-09-2014
Publisher: Oxford University Press (OUP)
Date: 21-08-2023
Publisher: Oxford University Press (OUP)
Date: 29-11-0001
Publisher: Oxford University Press (OUP)
Date: 02-03-2011
Publisher: American Astronomical Society
Date: 06-03-2019
Publisher: Oxford University Press (OUP)
Date: 20-05-2014
DOI: 10.1093/MNRAS/STU727
Publisher: Oxford University Press (OUP)
Date: 25-11-2016
Publisher: Oxford University Press (OUP)
Date: 11-05-2013
Publisher: Oxford University Press (OUP)
Date: 08-11-2010
Publisher: Oxford University Press (OUP)
Date: 12-04-2016
DOI: 10.1093/MNRAS/STW747
Publisher: Oxford University Press (OUP)
Date: 14-06-2018
Publisher: American Astronomical Society
Date: 22-02-2021
Publisher: Oxford University Press (OUP)
Date: 16-01-2018
DOI: 10.1093/MNRAS/STY127
Publisher: Oxford University Press (OUP)
Date: 06-06-2012
Publisher: EDP Sciences
Date: 09-2021
DOI: 10.1051/0004-6361/202140500
Abstract: Context. Galaxies are biased tracers of the underlying network of dark matter. The strength of this bias depends on various galaxy properties and on redshift. One of the methods used to study these dependences of the bias is measurement of galaxy clustering. Such studies are made using galaxy s les from various catalogues, which frequently bear their own problems related to s le selection methods. It is therefore crucial to understand how s le choice influences clustering measurements and which galaxy property is the most direct tracer of the galaxy environment. Aims. We investigate how different galaxy properties, such as luminosities in the u , g , r , J , and K bands, stellar mass, star formation rate, and specific star formation rate, trace the environment in the local universe. We also study the effect of survey flux limits on galaxy clustering measurements. Methods. We measure the two-point correlation function and marked correlation functions using the aforementioned properties as marks. We use a nearly stellar-mass-complete galaxy s le in the redshift range 0.1 z 0.16 from the Galaxy and Mass Assembly (GAMA) survey with a flux limit of r 19.8. Further, we impose a brighter flux limit of r 17.8 on our s le and repeated the measurements to study how this affects galaxy clustering analysis. We compare our results to measurements from the Sloan Digital Sky Survey with flux limits of r 17.8 and r 16.8. Results. We show that the stellar mass is the most direct tracer of galaxy environment, the K -band luminosity being a good substitute, although such a proxy s le misses close pairs of evolved, red galaxies. We also show that the u -band luminosity can be a proxy to the star formation rate in the context of galaxy clustering. We observe an effect of the survey flux limit on clustering studies s les with a higher flux limit (smaller magnitude) miss some information about close pairs of starburst galaxies.
Publisher: Cambridge University Press (CUP)
Date: 2021
DOI: 10.1017/PASA.2021.25
Abstract: We present an overview of the M iddle A ges G alaxy P roperties with I ntegral Field Spectroscopy (MAGPI) survey, a Large Program on the European Southern Observatory Very Large Telescope. MAGPI is designed to study the physical drivers of galaxy transformation at a lookback time of 3–4 Gyr, during which the dynamical, morphological, and chemical properties of galaxies are predicted to evolve significantly. The survey uses new medium-deep adaptive optics aided Multi-Unit Spectroscopic Explorer (MUSE) observations of fields selected from the Galaxy and Mass Assembly (GAMA) survey, providing a wealth of publicly available ancillary multi-wavelength data. With these data, MAGPI will map the kinematic and chemical properties of stars and ionised gas for a s le of 60 massive ( ${ }7 \\times 10^{10} {\\mathrm{M}}_\\odot$ ) central galaxies at $0.25 z .35$ in a representative range of environments (isolated, groups and clusters). The spatial resolution delivered by MUSE with Ground Layer Adaptive Optics ( $0.6-0.8$ arcsec FWHM) will facilitate a direct comparison with Integral Field Spectroscopy surveys of the nearby Universe, such as SAMI and MaNGA, and at higher redshifts using adaptive optics, for ex le, SINS. In addition to the primary (central) galaxy s le, MAGPI will deliver resolved and unresolved spectra for as many as 150 satellite galaxies at $0.25 z .35$ , as well as hundreds of emission-line sources at $z 6$ . This paper outlines the science goals, survey design, and observing strategy of MAGPI. We also present a first look at the MAGPI data, and the theoretical framework to which MAGPI data will be compared using the current generation of cosmological hydrodynamical simulations including EAGLE , Magneticum , HORIZON-AGN , and Illustris-TNG . Our results show that cosmological hydrodynamical simulations make discrepant predictions in the spatially resolved properties of galaxies at $z\\approx 0.3$ . MAGPI observations will place new constraints and allow for tangible improvements in galaxy formation theory.
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.
Publisher: Oxford University Press (OUP)
Date: 09-07-2013
Publisher: Oxford University Press (OUP)
Date: 13-09-2017
Publisher: European Southern Observatory (ESO)
Date: 2019
Publisher: Wiley
Date: 05-2013
Abstract: The stellar mass and metallicity are among the fundamental parameters of galaxies. An understanding of the interplay between those properties as well as their environmental dependence will give us a general picture of the physics and feedback processes ongoing in groups of galaxies. We study the relationships and environmental dependencies between the stellar mass, and gas metallicity for more than 1900 galaxies in groups up to redshift 0.35 using the Galaxy And Mass Assembly (GAMA) survey. Using a control s le of more than 28000 star‐forming field galaxies, we find evidence for a decrement of the gas metallicity for galaxies in groups. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Publisher: Oxford University Press (OUP)
Date: 20-10-2022
Abstract: We use stacked spectra of the host galaxies of photometrically identified Type Ia supernovae (SNe Ia) from the Dark Energy Survey (DES) to search for correlations between Hubble diagram residuals and the spectral properties of the host galaxies. Utilizing full spectrum fitting techniques on stacked spectra binned by Hubble residual, we find no evidence for trends between Hubble residuals and properties of the host galaxies that rely on spectral absorption features (& .3σ), such as stellar population age, metallicity, and mass-to-light ratio. However, we find significant trends between the Hubble residuals and the strengths of [O ii] (4.4σ) and the Balmer emission lines (3σ). These trends are weaker than the well-known trend between Hubble residuals and host galaxy stellar mass (7.2σ) that is derived from broad-band photometry. After light-curve corrections, we see fainter SNe Ia residing in galaxies with larger line strengths. We also find a trend (3σ) between Hubble residual and the Balmer decrement (a measure of reddening by dust) using H β and H γ. The trend, quantified by correlation coefficients, is slightly more significant in the redder SNe Ia, suggesting that the bluer SNe Ia are relatively unaffected by dust in the interstellar medium of the host and that dust contributes to current Hubble diagram scatter impacting the measurement of cosmological parameters.
Publisher: Oxford University Press (OUP)
Date: 02-2016
Publisher: American Astronomical Society
Date: 12-2005
DOI: 10.1086/497158
Publisher: EDP Sciences
Date: 11-2017
DOI: 10.1051/0004-6361/201731335
Abstract: In recent years, many studies have reported substantial populations of large galaxies with low surface brightness in local galaxy clusters. Various theories that aim to explain the presence of such ultra-diffuse galaxies (UDGs) have since been proposed. A key question that will help to distinguish between models is whether UDGs have counterparts in host haloes with lower masses, and if so, what their abundance as a function of halo mass is. We here extend our previous study of UDGs in galaxy clusters to galaxy groups. We measure the abundance of UDGs in 325 spectroscopically selected groups from the Galaxy And Mass Assembly (GAMA) survey. We make use of the overlapping imaging from the ESO Kilo-Degree Survey (KiDS), from which we can identify galaxies with mean surface brightnesses within their effective radii down to ~25.5 mag arcsec -2 in the r band. We are able to measure a significant overdensity of UDGs (with sizes r eff ≥ 1.5 kpc) in galaxy groups down to M 200 = 10 12 M ⊙ , a regime where approximately only one in ten groups contains a UDG that we can detect. We combine measurements of the abundance of UDGs in haloes that cover three orders of magnitude in halo mass, finding that their numbers scale quite steeply with halo mass: N UDG ( R R 200 ) ∝ M 200 1.11±0.07 . To better interpret this, we also measure the mass-richness relation for brighter galaxies down to M r * + 2.5 in the same GAMA groups, and find a much shallower relation of N Bright ( R R 200 ) ∝ M 200 0.78±0.05 . This shows that compared to bright galaxies, UDGs are relatively more abundant in massive clusters than in groups. We discuss the implications, but it is still unclear whether this difference is related to a higher destruction rate of UDGs in groups or if massive haloes have a positive effect on UDG formation.
Publisher: American Astronomical Society
Date: 08-2023
Abstract: In this empirical work, we aim to quantify the systematic uncertainties in stellar-mass ( M ⋆ ) estimates made from spectral energy distribution (SED) fitting through stellar population synthesis (SPS) for galaxies in the local Universe by using the dynamical mass ( M dyn ) estimator as an SED-independent check on stellar mass. We first construct a statistical model of the high-dimensional space of galaxy properties including size ( R e ), velocity dispersion ( σ e ), surface brightness ( I e ), mass-to-light ratio ( M ⋆ / L ), rest-frame color, Sérsic index ( n ), and dynamical mass ( M dyn ), and accounting for selection effects and covariant errors. We disentangle the correlations among galaxy properties and find that the variation in M ⋆ / M dyn is driven by σ e , Sérsic index and color. We use these parameters to calibrate an SED-independent M ⋆ estimator, M ˆ ⋆ . We find the random scatter of the relation M ⋆ − M ˆ ⋆ to be 0.108 dex and 0.147 dex for quiescent and star-forming galaxies, respectively. Finally, we inspect the residuals as a function of SPS parameters (dust, age, metallicity, and star formation rate) and spectral indices (H α , H δ , and D n 4000). For quiescent galaxies, ∼65% of the scatter can be explained by the uncertainty in SPS parameters, with dust and age being the largest sources of uncertainty. For star-forming galaxies, while age and metallicity are the leading factors, SPS parameters account for only ∼13% of the scatter. These results leave us with remaining unmodelled scatters of 0.055 dex and 0.122 dex for quiescent and star-forming galaxies, respectively. This can be interpreted as a conservative limit on the precision in M ⋆ that can be achieved via simple SPS modeling.
Publisher: Oxford University Press (OUP)
Date: 23-12-2016
Publisher: EDP Sciences
Date: 2023
DOI: 10.1051/0004-6361/202243193
Abstract: Aims. We investigate how different mid-infrared (mid-IR) properties of galaxies are correlated with the environment in which the galaxies are located. For this purpose, we first study the dependence of galaxy clustering on the absolute magnitude at 3.4 μm and redshift. Then, we look into the environmental dependence of mid-IR luminosities and the galaxy properties derived from these luminosities. We also explore how various IR galaxy luminosity selections influence the galaxy clustering measurements. Methods. We used a set of W 1 (3.4 μm) absolute magnitude ( M W 1 ) selected s les from the Galaxy and Mass Assembly (GAMA) survey matched with mid-IR properties from the Wide-field Infrared Survey Explorer (WISE) in the redshift range 0.07 ≤ z 0.43. We computed the galaxy two-point correlation function (2pCF) and compared the clustering lengths between subs les binned in M W 1 and in redshift. We also measured the marked correlation function (MCF), in which the galaxies are weighted by marks when measuring clustering statistics, using the luminosities in the WISE W 1 to W 4 (3.4 to 22 μm) bands as marks. Additionally, we compared the measurements of MCFs with different estimates of stellar mass and star formation rate (SFR) used as marks. Finally, we checked how different selections applied to the s le affect the clustering measurements. Results. We show strong clustering dependence on the W 1 absolute magnitude: galaxies brighter in the W 1 band are more strongly clustered than their fainter counterparts. We also observe a lack of significant redshift dependence of clustering in the redshift range 0.07 ≤ z 0.43. We show that although the W 1 and W 2 bands are direct indicators of stellar mass, a galaxy s le selected based on W 1 or W 2 bands does not perfectly show the clustering behaviour of a stellar mass-selected s le. The proxy relation between W 3 and W 4 bands and SFR is similar. We also demonstrate the influence of estimation techniques of stellar mass and SFR on the clustering measurements.
Publisher: Oxford University Press (OUP)
Date: 03-2011
Publisher: Oxford University Press (OUP)
Date: 12-04-2016
DOI: 10.1093/MNRAS/STW832
Publisher: American Astronomical Society
Date: 13-08-2010
Publisher: Oxford University Press (OUP)
Date: 30-12-2015
Publisher: Oxford University Press (OUP)
Date: 20-11-2015
Publisher: Oxford University Press (OUP)
Date: 06-07-2016
Publisher: Oxford University Press (OUP)
Date: 21-12-2012
Publisher: Cambridge University Press (CUP)
Date: 2015
DOI: 10.1017/PASA.2015.39
Abstract: Using both a theoretical and an empirical approach, we have investigated the frequency of low redshift galaxy-galaxy lensing systems in which the signature of 3D weak lensing might be directly detectable. We find good agreement between these two approaches. Using data from the Galaxy and Mass Assembly redshift survey we estimate the frequency of detectable weak lensing at low redshift. We find that below a redshift of z ~ 0.6, the probability of a galaxy being weakly lensed by γ ⩾ 0.02 is ~ 0.01. We have also investigated the feasibility of measuring the scatter in the M * − M h relation using shear statistics. We estimate that for a shear measurement error of Δγ = 0.02 (consistent with the sensitivity of the Direct Shear Mapping technique), with a s le of ~$50,000 spatially and spectrally resolved galaxies, the scatter in the M * − M h relation could be measured. While there are currently no existing IFU surveys of this size, there are upcoming surveys that will provide this data (e.g The Hobby-Eberly Telescope Dark Energy Experiment (HETDEX), surveys with Hector, and the Square Kilometre Array (SKA)).
Publisher: Springer Science and Business Media LLC
Date: 07-2020
Publisher: Oxford University Press (OUP)
Date: 12-10-2017
Publisher: Oxford University Press (OUP)
Date: 15-12-2022
Abstract: We have developed a pipeline called mentari to generate the far-ultraviolet to far-infrared spectral energy distribution (SED) of galaxies from the Dusty SAGEsemi-analytic galaxy formation model. Dusty SAGEincorporates dust-related processes directly on top of the basic ingredients of galaxy formation like gas infall, cooling, star formation, feedback, and mergers. We derive a physically motivated attenuation model from the computed dust properties in Dusty SAGE, so each galaxy has a self-consistent set of attenuation parameters based on the complicated dust physics that occurred across the galaxy’s assembly history. Then, we explore several dust emission templates to produce infrared spectra. Our results show that a physically-motivated attenuation model is better for obtaining a consistent multiwavelength description of galaxy formation and evolution, compared to using a constant attenuation. We compare our predictions with a compilation of observations and find that the fiducial model is in reasonable agreement with: (i) the observed z= 0 luminosity functions from the far-ultraviolet to far-infrared simultaneously, and hence (ii) the local cosmic SED in the same range, (iii) the rest-frame K-band luminosity function across 0 & z& 3, and (iv) the rest-frame far-ultraviolet luminosity function across 0 & z& 1. Our model underproduces the far-ultraviolet emission at z= 2 and z= 3, which can be improved by altering the AGN feedback and dust processes in Dusty SAGE, However, this combination thus worsens the agreement at z= 0, which suggests that more detailed treatment of such processes is required.
Publisher: Oxford University Press (OUP)
Date: 26-11-2014
Publisher: European Southern Observatory (ESO)
Date: 2019
Publisher: Oxford University Press (OUP)
Date: 29-08-2014
Publisher: Oxford University Press (OUP)
Date: 20-08-2015
Publisher: Oxford University Press (OUP)
Date: 26-07-2011
Publisher: Oxford University Press (OUP)
Date: 16-03-2019
DOI: 10.1093/MNRAS/STZ799
Publisher: Oxford University Press (OUP)
Date: 10-01-2015
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.
Publisher: Oxford University Press (OUP)
Date: 07-06-2016
Publisher: Oxford University Press (OUP)
Date: 16-02-2016
DOI: 10.1093/MNRAS/STW134
Publisher: Oxford University Press (OUP)
Date: 02-2012
Publisher: Oxford University Press (OUP)
Date: 09-2020
Abstract: We use KiDS weak lensing data to measure variations in mean halo mass as a function of several key galaxy properties (namely stellar colour, specific star formation rate, Sérsic index, and effective radius) for a volume-limited s le of GAMA galaxies in a narrow stellar mass range [M* ∼ (2–5) × 1010 M⊙]. This mass range is particularly interesting, inasmuch as it is where bimodalities in galaxy properties are most pronounced, and near to the break in both the galaxy stellar mass function and the stellar-to-halo mass relation (SHMR). In this narrow mass range, we find that both size and Sérsic index are better predictors of halo mass than either colour or SSFR, with the data showing a slight preference for Sérsic index. In other words, we find that mean halo mass is more tightly correlated with galaxy structure than either past star formation history or current star formation rate. Our results lead to an approximate lower bound on the dispersion in halo masses among log M* ≈ 10.5 galaxies: We find that the dispersion is ≳0.3 dex. This would imply either that offsets from the mean SHMR are closely coupled to size/structure or that the dispersion in the SHMR is larger than what past results have suggested. Our results thus provide new empirical constraints on the relationship between stellar and halo mass assembly at this particularly interesting mass range.
Publisher: Oxford University Press (OUP)
Date: 11-05-2017
Publisher: EDP Sciences
Date: 10-2020
DOI: 10.1051/0004-6361/202038835
Abstract: Measuring cosmic shear in wide-field imaging surveys requires accurate knowledge of the redshift distribution of all sources. The clustering-redshift technique exploits the angular cross-correlation of a target galaxy s le with unknown redshifts and a reference s le with known redshifts. It represents an attractive alternative to colour-based methods of redshift calibration. Here we test the performance of such clustering redshift measurements using mock catalogues that resemble the Kilo-Degree Survey (KiDS). These mocks are created from the MICE simulation and closely mimic the properties of the KiDS source s le and the overlapping spectroscopic reference s les. We quantify the performance of the clustering redshifts by comparing the cross-correlation results with the true redshift distributions in each of the five KiDS photometric redshift bins. Such a comparison to an informative model is necessary due to the incompleteness of the reference s les at high redshifts. Clustering mean redshifts are unbiased at |Δ z | 0.006 under these conditions. The redshift evolution of the galaxy bias of the reference and target s les represents one of the most important systematic errors when estimating clustering redshifts. It can be reliably mitigated at this level of precision using auto-correlation measurements and self-consistency relations, and will not become a dominant source of systematic error until the arrival of Stage-IV cosmic shear surveys. Using redshift distributions from a direct colour-based estimate instead of the true redshift distributions as a model for comparison with the clustering redshifts increases the biases in the mean to up to |Δ z |∼0.04. This indicates that the interpretation of clustering redshifts in real-world applications will require more sophisticated (parameterised) models of the redshift distribution in the future. If such better models are available, the clustering-redshift technique promises to be a highly complementary alternative to other methods of redshift calibration.
Publisher: Oxford University Press (OUP)
Date: 30-09-2015
Publisher: Oxford University Press (OUP)
Date: 19-06-2015
Publisher: Oxford University Press (OUP)
Date: 21-08-2023
Publisher: American Astronomical Society
Date: 06-11-2020
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.
Publisher: Oxford University Press (OUP)
Date: 28-02-2017
DOI: 10.1093/MNRAS/STX503
Publisher: Oxford University Press (OUP)
Date: 21-11-2019
Publisher: Oxford University Press (OUP)
Date: 12-09-2017
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.
Publisher: Oxford University Press (OUP)
Date: 20-11-2015
Publisher: Oxford University Press (OUP)
Date: 19-02-2016
DOI: 10.1093/MNRAS/STW381
Publisher: Oxford University Press (OUP)
Date: 07-02-2013
DOI: 10.1093/MNRAS/STT030
Publisher: Oxford University Press (OUP)
Date: 12-02-2014
Publisher: EDP Sciences
Date: 10-2020
DOI: 10.1051/0004-6361/202038693
Abstract: We simultaneously present constraints on the stellar-to-halo mass relation for central and satellite galaxies through a weak lensing analysis of spectroscopically classified galaxies. Using overlapping data from the fourth data release of the Kilo-Degree Survey (KiDS), and the Galaxy And Mass Assembly survey (GAMA), we find that satellite galaxies are hosted by halo masses that are 0.53 ± 0.39 dex (68% confidence, 3 σ detection) smaller than those of central galaxies of the same stellar mass (for a stellar mass of log( M ⋆ / M ⊙ ) = 10.6). This is consistent with galaxy formation models, whereby infalling satellite galaxies are preferentially stripped of their dark matter. We find consistent results with similar uncertainties when comparing constraints from a standard azimuthally averaged galaxy-galaxy lensing analysis and a two-dimensional likelihood analysis of the full shear field. As the latter approach is somewhat biased due to the lens incompleteness and as it does not provide any improvement to the precision when applied to actual data, we conclude that stacked tangential shear measurements are best-suited for studies of the galaxy-halo connection.
Publisher: Oxford University Press (OUP)
Date: 17-05-2023
Abstract: We use the latest parallaxes measurements from Gaia DR3 to obtain a geometric calibration of the tip of the red giant branch (TRGB) in Cousins I magnitudes as a standard candle for cosmology. We utilize the following surveys: SkyMapper DR3, APASS DR9, ATLAS Refcat2, and Gaia DR3 synthetic photometry to obtain multiple zero-point calibrations of the TRGB magnitude, $M_{I}^{TRGB}$. Our s le contains Milky Way halo stars at high galactic latitudes (|b| & 36) where the impact of metallicity, dust, and crowding are minimized. The magnitude of the TRGB is identified using Sobel edge detection, but this approach introduced a systematic offset. To address this issue, we utilized simulations with parsec isochrones and showed how to calibrate and remove this bias. Applying our method within the colour range where the slope of the TRGB is relatively flat for metal-poor halo stars (1.55 & (BP − RP) & 2.25), we find a weighted average $M_{I}^{TRGB} = -4.042 \pm 0.041$ (stat) ±0.031 (sys) mag. A geometric calibration of the Milky Way TRGB has the benefit of being independent of other distance indicators and will help probe systematics in the local distance ladder, leading to improved measurements of the Hubble constant.
Publisher: Oxford University Press (OUP)
Date: 08-03-2013
DOI: 10.1093/MNRAS/STT156
No related organisations have been discovered for Edward Taylor.
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End Date: 10-2021
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Amount: $340,160.00
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