Andrew R. Casey
A5024917971- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Gamma-ray bursts and supernovae
- Astrophysics and Star Formation Studies
- Astronomical Observations and Instrumentation
- Astro and Planetary Science
- Astrophysical Phenomena and Observations
- Galaxies: Formation, Evolution, Phenomena
- Adaptive optics and wavefront sensing
- SAS software applications and methods
- Calibration and Measurement Techniques
- Geophysics and Gravity Measurements
- Pulsars and Gravitational Waves Research
- Scientific Research and Discoveries
- Spectroscopy and Chemometric Analyses
- Atmospheric Ozone and Climate
- History and Developments in Astronomy
- Atomic and Subatomic Physics Research
- Astronomical and nuclear sciences
- Optical Systems and Laser Technology
- Astrophysics and Cosmic Phenomena
- Inertial Sensor and Navigation
- Relativity and Gravitational Theory
- Quantum, superfluid, helium dynamics
- Space Exploration and Technology
Monash University
2017-2025
ARC Centre of Excellence for All-sky Astrophysics
2019-2025
Royal Holloway University of London
2025
The Ohio State University
2025
ASTRO-3D
2019-2024
Australian National University
2011-2024
Flatiron Health (United States)
2024
Flatiron Institute
2024
UNSW Sydney
2024
Australian Regenerative Medicine Institute
2019-2022
We present the first public version (v0.2) of open-source and community-developed Python package, Astropy. This package provides core astronomy-related functionality to community, including support for domain-specific file formats such as Flexible Image Transport System (FITS) files, Virtual Observatory (VO) tables, common ASCII table formats, unit physical quantity conversions, constants specific astronomy, celestial coordinate time transformations, world system (WCS) support, generalized...
The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) has been in operation since 2014 July. This paper describes second data release from this phase, and 14th SDSS overall (making Data Release Fourteen or DR14). makes taken by SDSS-IV its first two years (2014–2016 July) public. Like all previous releases, DR14 is cumulative, including most recent reductions calibrations phase began operations 2000. New public extended Baryon Oscillation Spectroscopic Survey; Apache Point...
The GALAH survey is a large high-resolution spectroscopic using the newly commissioned HERMES spectrograph on Anglo-Australian Telescope. provides (R ~28,000) spectra in four passbands for 392 stars simultaneously over 2 degree field of view. goal to unravel formation and evolutionary history Milky Way, fossil remnants ancient star events which have been disrupted are now dispersed throughout Galaxy. Chemical tagging seeks identify such solely from their common unique chemical signatures;...
The ensemble of chemical element abundance measurements for stars, along with precision distances and orbit properties, provides high-dimensional data to study the evolution Milky Way. With this third release Galactic Archaeology HERMES (GALAH) survey, we publish 678 423 spectra 588 571 mostly nearby stars (81.2% are within <2 kpc), observed spectrograph at Anglo-Australian Telescope. This (hereafter GALAH+ DR3) includes all observations from GALAH Phase 1 (bright, main, faint 70%),...
The Galactic Archaeology with HERMES (GALAH) survey is a large-scale stellar spectroscopic of the Milky Way and designed to deliver chemical information complementary large number stars covered by $Gaia$ mission. We present GALAH second public data release (GALAH DR2) containing 342,682 stars. For these stars, collaboration provides parameters abundances for up 23 elements community. Here we target selection, observation, reduction detailed explanation how spectra were analysed estimate...
Abstract The data and analysis methodology used for the SDSS/APOGEE Data Releases 13 14 are described, highlighting differences from DR12 presented in Holtzman et al. Some improvement handling of telluric absorption persistence is demonstrated. derivation calibration stellar parameters, chemical abundances, respective uncertainties along with ranges over which was performed. known issues public related to effective temperatures (DR13), surface gravity (DR13 DR14), C N abundances dwarfs DR14)...
We use the second data releases of ESA Gaia astrometric survey and high-resolution GALAH spectroscopic to analyse structure our Galaxy's disc components. With GALAH, we separate alpha-rich alpha-poor discs (with respect Fe), which are superposed in both position velocity space, examine their distributions action space. study distribution stars zV_z phase plane, for V_phi V_R, recover remarkable "phase spiral" discovered by Gaia. identify anticipated quadrupole signature a tilted ellipsoid...
The Galactic Archaeology with HERMES (GALAH) Survey is a massive observational project to trace the Milky Way's history of star formation, chemical enrichment, stellar migration and minor mergers. Using high-resolution (R$\simeq$28,000) spectra taken High Efficiency Resolution Multi-Element Spectrograph (HERMES) instrument at Anglo-Australian Telescope (AAT), GALAH will determine parameters abundances up 29 elements for one million stars. Selecting targets from colour-unbiased catalogue...
SDSS-V will be an all-sky, multi-epoch spectroscopic survey of over six million objects. It is designed to decode the history Milky Way, trace emergence chemical elements, reveal inner workings stars, and investigate origin planets. also create integral-field map gas in Galaxy Local Group that 1,000x larger than current state art at high enough spatial resolution self-regulation mechanisms galactic ecosystems. pioneer systematic, monitoring across whole sky, revealing changes on timescales...
The eighteenth data release of the Sloan Digital Sky Surveys (SDSS) is first one for SDSS-V, fifth generation survey. SDSS-V comprises three primary scientific programs, or "Mappers": Milky Way Mapper (MWM), Black Hole (BHM), and Local Volume (LVM). This contains extensive targeting information two multi-object spectroscopy programs (MWM BHM), including input catalogs selection functions their numerous objectives. We describe production databases calibration- scientifically-focused...
In the last 15 years different ground-based spectroscopic surveys have been started (and completed) with general aim of delivering stellar parameters and elemental abundances for large samples Galactic stars, complementing Gaia astrometry. Among those surveys, Gaia-ESO Public Spectroscopic Survey (GES), only one performed on a 8m class telescope, was designed to target 100,000 stars using FLAMES ESO VLT (both Giraffe UVES spectrographs), covering all Milky Way populations, special focus open...
Context. The Gaia-ESO Public Spectroscopic Survey is an ambitious project designed to obtain astrophysical parameters and elemental abundances for 100 000 stars, including large representative samples of the stellar populations in Galaxy, a well-defined sample 60 (plus 20 archive) open clusters. We provide internally consistent results calibrated on benchmark stars star clusters, extending across very wide range ages. This provides legacy data set intrinsic value, equally wide-ranging...
The Transiting Exoplanet Survey Satellite (TESS) will provide high precision time-series photometry for millions of stars with at least a half-hour cadence. Of particular interest are the circular regions 12-degree radius centered around ecliptic poles that be observed continuously full year. Spectroscopic stellar parameters desirable to characterize and select suitable targets TESS, whether they focused on exploring exoplanets, astrophysics, or Galactic archaeology. Here, we present...
The SkyMapper Southern Sky Survey is carrying out a search for the most metal-poor stars in Galaxy. It identifies candidates by way of its unique filter set which allows estimation stellar atmospheric parameters. includes narrow centered on Ca ii K 3933 Å line, enabling robust estimate metallicity. Promising are then confirmed with spectroscopy. We present analysis Magellan Inamori Kyocera Echelle high-resolution spectroscopy 122 found first two years commissioning observations. Forty-one...
It is well established that stellar effective temperatures determined from photometry and spectroscopy yield systematically different results. We describe a new, simple method to correct spectroscopically derived ("excitation temperatures") of metal-poor stars based on literature sample with -3.3<[Fe/H]<-2.5. Excitation were FeI line abundances in high-resolution optical spectra the wavelength range ~3700 ~7000A, although shorter ranges, up 4750 6800A, can also be employed, compared...
The spatial distribution of elemental abundances in the disc our Galaxy gives insights both on its assembly process and subsequent evolution, stellar nucleogenesis different elements. Gradients can be traced using several types objects as, for instance, (young old) stars, open clusters, HII regions, planetary nebulae. We aim at tracing radial distributions elements produced through nucleosynthetic channels -the alpha-elements O, Mg, Si, Ca Ti, iron-peak Fe, Cr, Ni Sc - by Gaia-ESO idr4...
We use Gaia-ESO Survey iDR4 data to explore the Mg-Al anti-correlation in globular clusters, that were observed as calibrators, a demonstration of quality and analysis. The results compare well with available literature, within 0.1 dex or less, after small (compared internal spreads) offset between UVES GIRAFFE 0.10-0.15 was taken into account. In particular, we present for first time NGC 5927, one most metal-rich clusters studied literature so far [Fe/H]=-0.49 dex, included connect open...
We introduce the 4-metre Multi-Object Spectroscopic Telescope (4MOST), a new high-multiplex, wide-field spectroscopic survey facility under development for four-metre-class Visible and Infrared Survey Astronomy (VISTA) at Paranal. Its key specifications are: large field of view (FoV) 4.2 square degrees high multiplex capability, with 1624 fibres feeding two low-resolution spectrographs ($R = λ/Δλ\sim 6500$), 812 transferring light to high-resolution spectrograph \sim 20\,000$). After...
Photometry alone is not sufficient to unambiguously distinguish between ultra-faint star clusters and dwarf galaxies because of their overlap in morphological properties. Here we report on VLT/GIRAFFE spectra candidate member stars two recently discovered satellites Reticulum 2 Horologium 1, obtained as part the ongoing Gaia-ESO Survey. We identify 18 members 5 1. find have a velocity dispersion ~3.22 km/s, implying M/L ratio ~ 500. inferred stellar parameters for all candidates mean...
We report the discovery of a nearby dwarf galaxy in constellation Hydrus, between Large and Small Magellanic Clouds. Hydrus 1 is mildy elliptical ultra-faint system with luminosity $M_V\sim$ -4.7 size $\sim$ 50 pc, located 28 kpc from Sun 24 LMC. From spectroscopy 30 member stars, we measure velocity dispersion 2.7 km/s find tentative evidence for radial gradient consistent 3 rotation. 1's indicates that dark matter dominated, but its dynamical mass-to-light ratio M/L 66 significantly...
The radial metallicity distribution in the Galactic thin disc represents a crucial constraint for modelling formation and evolution. Open clusters allow us to derive both its evolution over time. In this paper we perform first investigation of present-day based on [Fe/H] determinations late type members pre-main-sequence clusters. Because their youth, these are therefore essential tracing current inter-stellar medium metallicity. We used products Gaia-ESO Survey analysis 12 young regions...
Open clusters are unique tracers of the history our own Galaxy's disk. According to membership analysis based on \textit{Gaia} astrometry, out 226 potential falling in footprint GALAH or APOGEE, we find that 205 have secure members were observed by at least one survey. Furthermore, 134 high-quality spectroscopic data use determine their chemical composition. We leverage this information study distribution throughout Galactic disk 21 elements, from C Eu. The radial metallicity gradient...