The GALAH survey: third data release

Buder, Sven and Sharma, Sanjib and Kos, Janez and Amarsi, Anish M. and Nordlander, Thomas and Lind, Karin and Martell, Sarah L. and Asplund, Martin and Bland-Hawthorn, Joss and Casey, Andrew R. and de Silva, Gayandhi M. and D'Orazi, Valentina and Freeman, Ken C. and Hayden, Michael R. and Lewis, Geraint F. and Lin, Jane and Schlesinger, Katharine J. and Simpson, Jeffrey D. and Stello, Dennis and Zucker, Daniel B. and Zwitter, Tomaz and Beeson, Kevin L. and Buck, Tobias and Casagrande, Luca and Clark, Jake T. and Cotar, Klemen and Da Costa, Gary S. and de Grijs, Richard and Feuillet, Diane and Horner, Jonathan and Kafle, Prajwal R. and Khanna, Shourya and Kobayashi, Chiaki and Liu, Fan and Montet, Benjamin T. and Nandakumar, Govind and Nataf, David M. and Ness, Melissa K. and Spina, Lorenzo and Tepper-Garcia, Thor and Ting, Yuan-Sen and Traven, Gregor and Vogrincic, Rok and Wittenmyer, Robert A. and Wyse, Rosemary F. G. and Zerjal, Marusa and Galah Collaboration (2021) The GALAH survey: third data release. Monthly Notices of the Royal Astronomical Society, 506. pp. 150-201. ISSN 0035-8711

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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 <2 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 >75 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.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: C. 2021 The Author(s). Published version deposited in accordance with the copyright policy of the publisher.
Faculty/School / Institute/Centre: Current - Institute for Advanced Engineering and Space Sciences - Centre for Astrophysics (1 Aug 2018 -)
Faculty/School / Institute/Centre: Current - Institute for Advanced Engineering and Space Sciences - Centre for Astrophysics (1 Aug 2018 -)
Date Deposited: 27 Jul 2021 02:05
Last Modified: 20 Sep 2021 05:00
Uncontrolled Keywords: data analysis; observational; surveys; stars; abundances; fundamental parameters; astrophysics; astrophysics; of galaxies; solar and stellar astrophysics
Fields of Research (2008): 02 Physical Sciences > 0201 Astronomical and Space Sciences > 020110 Stellar Astronomy and Planetary Systems
Fields of Research (2020): 51 PHYSICAL SCIENCES > 5101 Astronomical sciences > 510109 Stellar astronomy and planetary systems
Socio-Economic Objectives (2008): E Expanding Knowledge > 97 Expanding Knowledge > 970102 Expanding Knowledge in the Physical Sciences
Socio-Economic Objectives (2020): 28 EXPANDING KNOWLEDGE > 2801 Expanding knowledge > 280120 Expanding knowledge in the physical sciences
Identification Number or DOI: https://doi.org/10.1093/mnras/stab1242
URI: http://eprints.usq.edu.au/id/eprint/42813

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