ORCID Profile
0000-0002-6327-9147
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Astronomical and Space Sciences | Cosmology and Extragalactic Astronomy | Galactic Astronomy | Astronomical and Space Instrumentation
Expanding Knowledge in the Physical Sciences | Scientific Instruments | Expanding Knowledge in the Information and Computing Sciences |
Publisher: American Astronomical Society
Date: 20-03-2018
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: Oxford University Press (OUP)
Date: 05-02-2019
DOI: 10.1093/MNRAS/STZ363
Publisher: American Astronomical Society
Date: 03-11-2016
Publisher: American Astronomical Society
Date: 12-05-2017
Publisher: Oxford University Press (OUP)
Date: 08-08-2017
Publisher: Oxford University Press (OUP)
Date: 23-12-2019
Abstract: We present an analysis of the gas dynamics of star-forming galaxies at z ∼ 1.5 using data from the KMOS Galaxy Evolution Survey. We quantify the morphology of the galaxies using HSTcandels imaging parametrically and non-parametrically. We combine the H α dynamics from KMOS with the high-resolution imaging to derive the relation between stellar mass (M*) and stellar specific angular momentum (j*). We show that high-redshift star-forming galaxies at z ∼ 1.5 follow a power-law trend in specific stellar angular momentum with stellar mass similar to that of local late-type galaxies of the form j* ∝ M$_*^{0.53\\, \\pm \\, 0.10}$. The highest specific angular momentum galaxies are mostly disc-like, although generally both peculiar morphologies and disc-like systems are found across the sequence of specific angular momentum at a fixed stellar mass. We explore the scatter within the j* – M* plane and its correlation with both the integrated dynamical properties of a galaxy (e.g. velocity dispersion, Toomre Qg, H α star formation rate surface density ΣSFR) and its parametrized rest-frame UV / optical morphology (e.g. Sérsic index, bulge to total ratio, clumpiness, asymmetry, and concentration). We establish that the position in the j* – M* plane is strongly correlated with the star-formation surface density and the clumpiness of the stellar light distribution. Galaxies with peculiar rest-frame UV / optical morphologies have comparable specific angular momentum to disc- dominated galaxies of the same stellar mass, but are clumpier and have higher star formation rate surface densities. We propose that the peculiar morphologies in high-redshift systems are driven by higher star formation rate surface densities and higher gas fractions leading to a more clumpy interstellar medium.
Publisher: American Astronomical Society
Date: 22-06-2017
Publisher: EDP Sciences
Date: 06-2018
DOI: 10.1051/0004-6361/201732373
Abstract: The Virgo Environmental Survey Tracing Ionised Gas Emission (VESTIGE) is a blind narrow-band H α + [NII] imaging survey carried out with MegaCam at the Canada-France-Hawaii Telescope. During pilot observations taken in the spring of 2016 we observed NGC 4330, an intermediate mass ( M * ≃ 10 9.8 M ⊙ ) edge-on star forming spiral currently falling into the core of the Virgo cluster. While previous H α observations showed a clumpy complex of ionised gas knots outside the galaxy disc, new deep observations revealed a low surface brightness ~10 kpc tail exhibiting a peculiar filamentary structure. The filaments are remarkably parallel to one another and clearly indicate the direction of motion of the galaxy in the Virgo potential. Motivated by the detection of these features which indicate ongoing gas stripping, we collected literature photometry in 15 bands from the far-UV to the far-IR and deep optical long-slit spectroscopy using the FORS2 instrument at the ESO Very Large Telescope. Using a newly developed Monte Carlo code that jointly fits spectroscopy and photometry, we reconstructed the star formation histories in apertures along the major axis of the galaxy. Our results have been validated against the output of CIGALE, a fitting code which has been previously used for similar studies. We found a clear outside-in gradient with radius of the time when the quenching event started: the outermost radii were stripped ~500 Myr ago, while the stripping reached the inner 5 kpc from the centre in the last 100 Myr. Regions at even smaller radii are currently still forming stars fueled by the presence of HI and H 2 gas. When compared to statistical studies of the quenching timescales in the local Universe we find that ram pressure stripping of the cold gas is an effective mechanism to reduce the transformation times for galaxies falling into massive clusters. Future systematic studies of all the active galaxies observed by VESTIGE in the Virgo cluster will extend these results to a robust statistical framework.
Publisher: American Astronomical Society
Date: 17-05-2017
Publisher: Springer Science and Business Media LLC
Date: 03-2017
DOI: 10.1038/NATURE21685
Abstract: In the cold dark matter cosmology, the baryonic components of galaxies-stars and gas-are thought to be mixed with and embedded in non-baryonic and non-relativistic dark matter, which dominates the total mass of the galaxy and its dark-matter halo. In the local (low-redshift) Universe, the mass of dark matter within a galactic disk increases with disk radius, becoming appreciable and then dominant in the outer, baryonic regions of the disks of star-forming galaxies. This results in rotation velocities of the visible matter within the disk that are constant or increasing with disk radius-a hallmark of the dark-matter model. Comparisons between the dynamical mass, inferred from these velocities in rotational equilibrium, and the sum of the stellar and cold-gas mass at the peak epoch of galaxy formation ten billion years ago, inferred from ancillary data, suggest high baryon fractions in the inner, star-forming regions of the disks. Although this implied baryon fraction may be larger than in the local Universe, the systematic uncertainties (owing to the chosen stellar initial-mass function and the calibration of gas masses) render such comparisons inconclusive in terms of the mass of dark matter. Here we report rotation curves (showing rotation velocity as a function of disk radius) for the outer disks of six massive star-forming galaxies, and find that the rotation velocities are not constant, but decrease with radius. We propose that this trend arises because of a combination of two main factors: first, a large fraction of the massive high-redshift galaxy population was strongly baryon-dominated, with dark matter playing a smaller part than in the local Universe and second, the large velocity dispersion in high-redshift disks introduces a substantial pressure term that leads to a decrease in rotation velocity with increasing radius. The effect of both factors appears to increase with redshift. Qualitatively, the observations suggest that baryons in the early (high-redshift) Universe efficiently condensed at the centres of dark-matter haloes when gas fractions were high and dark matter was less concentrated.
Publisher: American Astronomical Society
Date: 28-11-2019
Publisher: Oxford University Press (OUP)
Date: 21-08-2023
Publisher: Oxford University Press (OUP)
Date: 05-05-2021
Abstract: In this paper, we analyse the statistics of the 2D gas-phase oxygen abundance distributions of 100 nearby galaxies drawn from the Calar Alto Legacy Integral Field spectroscopy Area survey. After removing the large-scale radial metallicity gradient, we compute the two-point correlation functions of the resulting metallicity fluctuation maps. We detect correlations in the majority of our targets, which we show are significantly in excess of what is expected due to beam-smearing, and are robust against the choice of metallicity diagnostic. We show that the correlation functions are generally well-fit by the predictions of a simple model for stochastic metal injection coupled with diffusion, and from the model we show that, after accounting for the effects of both beam smearing and noise, the galaxies in our s le have characteristic correlation lengths of ∼1 kpc. Correlation lengths increase with both stellar mass and star formation rate, but show no significant variation with Hubble type, barredness, or merging state. We also find no evidence for a theoretically predicted relationship between gas velocity dispersion and correlation length, though this may be due to the small dynamic range in gas velocity dispersion across our s le. Our results suggest that measurements of 2D metallicity correlation functions can be a powerful tool for studying galaxy evolution.
Publisher: American Astronomical Society
Date: 19-03-2020
Publisher: American Astronomical Society
Date: 24-01-2017
Publisher: American Astronomical Society
Date: 12-03-2018
Publisher: Oxford University Press (OUP)
Date: 31-07-2021
Abstract: Accurate astrometry is a key deliverable for the next generation of multiconjugate adaptive optics (MCAO) systems. The MCAO-Assisted Visible Imager and Spectrograph (MAVIS) is being designed for the Very Large Telescope Adaptive Optics Facility and must achieve 150 $\\mu$as astrometric precision (50 $\\mu$as goal). To test this before going on-sky, we have created MAVIS Image Simulator (mavisim), a tool to simulate MAVIS images. mavisim accounts for three major sources of astrometric error: high- and low-order point spread function (PSF) spatial variability, tip–tilt residual error, and static field distortion. When exploring the impact of these three error terms alone, we recover an astrometric accuracy of 50 $\\mu$as for all stars brighter than m = 19 in a 30 s integration using PSF-fitting photometry. We also assess the feasibility of MAVIS detecting an intermediate-mass black hole (IMBH) in a Milky Way globular cluster. We use an N-body simulation of an NGC 3201-like cluster with a central 1500 M⊙ IMBH as input to mavisim and recover the velocity dispersion profile from proper motion measurements. Under favourable astrometric conditions, the dynamical signature of the IMBH is detected with a precision of ∼0.20 km s−1 in the inner ∼4 arcsec of the cluster where Hubble Space Telescope (HST) is confusion limited. This precision is comparable to measurements made by Gaia, HST, and Multi Unit Spectroscopic Explorer (MUSE) in the outer ∼60 arcsec of the cluster. This study is the first step towards building a science-driven astrometric error budget for an MCAO system and a prediction of what MAVIS could do once on sky.
Publisher: American Astronomical Society
Date: 08-2016
Publisher: SPIE
Date: 13-12-2020
DOI: 10.1117/12.2561930
Publisher: SPIE-Intl Soc Optical Eng
Date: 27-01-2022
Publisher: American Astronomical Society
Date: 30-01-2015
Publisher: SPIE
Date: 13-12-2020
DOI: 10.1117/12.2561433
Publisher: American Astronomical Society
Date: 09-08-2016
Publisher: Oxford University Press (OUP)
Date: 21-08-2023
Publisher: Oxford University Press (OUP)
Date: 31-10-2020
Abstract: We present an analysis of the chemical abundance properties of ≈650 star-forming galaxies at z ≈ 0.6 – 1.8. Using integral-field observations from the K - band Multi-Object Spectrograph (KMOS), we quantify the [N ii]/Hα emission-line ratio, a proxy for the gas-phase Oxygen abundance within the interstellar medium. We define the stellar mass – metallicity relation at z ≈ 0.6 – 1.0 and z ≈ 1.2 – 1.8 and analyse the correlation between the scatter in the relation and fundamental galaxy properties (e.g. Hα star-formation rate, Hα specific star-formation rate, rotation dominance, stellar continuum half-light radius and Hubble-type morphology). We find that for a given stellar mass, more highly star-forming, larger and irregular galaxies have lower gas-phase metallicities, which may be attributable to their lower surface mass densities and the higher gas fractions of irregular systems. We measure the radial dependence of gas-phase metallicity in the galaxies, establishing a median, beam smearing-corrected, metallicity gradient of ΔZ/ΔR= 0.002 ± 0.004 dex kpc−1, indicating on average there is no significant dependence on radius. The metallicity gradient of a galaxy is independent of its rest-frame optical morphology, whilst correlating with its stellar mass and specific star-formation rate, in agreement with an inside-out model of galaxy evolution, as well as its rotation dominance. We quantify the evolution of metallicity gradients, comparing the distribution of ΔZ/ΔR in our s le with numerical simulations and observations at z ≈ 0 – 3. Galaxies in our s le exhibit flatter metallicity gradients than local star-forming galaxies, in agreement with numerical models in which stellar feedback plays a crucial role redistributing metals.
Publisher: American Astronomical Society
Date: 24-07-2019
Publisher: American Astronomical Society
Date: 03-2021
Abstract: We investigate what drives the redshift evolution of the typical electron density ( n e ) in star-forming galaxies, using a s le of 140 galaxies drawn primarily from KMOS 3D (0.6 z 2.6) and 471 galaxies from SAMI ( z 0.113). We select galaxies that do not show evidence of active galactic nucleus activity or outflows to constrain the average conditions within H ii regions. Measurements of the [S ii ] λ 6716/[S ii ] λ 6731 ratio in four redshift bins indicate that the local n e in the line-emitting material decreases from 187 cm −3 at z ∼ 2.2 to 32 cm −3 at z ∼ 0, consistent with previous results. We use the H α luminosity to estimate the rms n e averaged over the volumes of star-forming disks at each redshift. The local and volume-averaged n e evolve at similar rates, hinting that the volume filling factor of the line-emitting gas may be approximately constant across 0 ≲ z ≲ 2.6. The KMOS 3D and SAMI galaxies follow a roughly monotonic trend between n e and star formation rate, but the KMOS 3D galaxies have systematically higher n e than the SAMI galaxies at a fixed offset from the star-forming main sequence, suggesting a link between the n e evolution and the evolving main sequence normalization. We quantitatively test potential drivers of the density evolution and find that n e (rms) , suggesting that the elevated n e in high- z H ii regions could plausibly be the direct result of higher densities in the parent molecular clouds. There is also tentative evidence that n e could be influenced by the balance between stellar feedback, which drives the expansion of H ii regions, and the ambient pressure, which resists their expansion.
Publisher: American Astronomical Society
Date: 08-09-2017
Publisher: American Astronomical Society
Date: 09-01-2017
Publisher: Oxford University Press (OUP)
Date: 07-03-2016
DOI: 10.1093/MNRAS/STW502
Publisher: American Astronomical Society
Date: 04-12-2017
Publisher: Oxford University Press (OUP)
Date: 27-03-2019
DOI: 10.1093/MNRAS/STZ855
Publisher: American Astronomical Society
Date: 09-04-2019
No related organisations have been discovered for Jon Trevor Mendel.
Start Date: 10-2021
End Date: 09-2024
Amount: $645,000.00
Funder: Australian Research Council
View Funded ActivityStart Date: 11-2022
End Date: 12-2023
Amount: $1,749,940.00
Funder: Australian Research Council
View Funded Activity