The GALAH Survey: chemical tagging and chrono-chemodynamics of accreted halo stars with GALAH+ DR3 and Gaia eDR3
Article
Article Title | The GALAH Survey: chemical tagging and chrono-chemodynamics of accreted halo stars with GALAH+ DR3 and Gaia eDR3 |
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ERA Journal ID | 1074 |
Article Category | Article |
Authors | Buder, Sven (Author), Lind, Karin (Author), Ness, Melissa K. (Author), Feuillet, Diane K. (Author), Horta, Danny (Author), Monty, Stephanie (Author), Buck, Tobias (Author), Nordlander, Thomas (Author), Bland-Hawthorn, Joss (Author), Casey, Andrew R. (Author), de Silva, Gayandhi M. (Author), D'Orazi, Valentina (Author), Freeman, Ken C. (Author), Hayden, Michael R. (Author), Kos, Janez (Author), Martell, Sarah L. (Author), Lewis, Geraint F. (Author), Lin, Jane (Author), Schlesinger, Katharine J. (Author), Sharma, Sanjib (Author), Simpson, Jeffrey D. (Author), Stello, Dennis (Author), Zucker, Daniel B. (Author), Zwitter, Tomaz (Author), Ciuca, Ioana (Author), Horner, Jonathan (Author), Kobayashi, Chiaki (Author), Ting, Yuan-Sen (Author) and Wyse, Rosemary F. G. (Author) |
Journal Title | Monthly Notices of the Royal Astronomical Society |
Journal Citation | 510 (2), pp. 2407-2436 |
Number of Pages | 30 |
Year | 2022 |
Publisher | Oxford University Press |
Place of Publication | United Kingdom |
ISSN | 0035-8711 |
1365-2966 | |
Digital Object Identifier (DOI) | https://doi.org/10.1093/mnras/stab3504 |
Web Address (URL) | https://academic.oup.com/mnras/article/510/2/2407/6449023 |
Abstract | Since the advent of Gala astrometry, it is possible to identify massive accreted systems within the Galaxy through their unique dynamical signatures. One such system, Goia-Sausage-Enceladus (GSE), appears to be an early 'building block' given its virial mass > 1010 Mo 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 -o, 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/Min] in GALAH+ DR3, We provide tables of our selections and report the chrono-chetnodynamical properties (age, chemistry, and dynamics), Through a previously reported clean dynamical selection of USE stars, including 30 < OR/ kpc km s-1 < 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 example mean OR/ kpc kin s-1 = 26'914. We find only (29 + 1) per cent of the USE 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. |
Keywords | The Galaxy; Galaxy: formation; Galaxy: halo; Galaxy: abundances; Galaxy: kinematics and dynamics; Astrophysics - Astrophysics of Galaxies; Astrophysics - Solar and Stellar Astrophysics |
ANZSRC Field of Research 2020 | 510104. Galactic astronomy |
510109. Stellar astronomy and planetary systems | |
Public Notes | This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2022 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. |
Byline Affiliations | Australian National University |
Stockholm University, Sweden | |
Columbia University, United States | |
Lund Observatory, Sweden | |
Liverpool John Moores University, United Kingdom | |
Leibniz Institute for Astrophysics, Germany | |
ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions, Australia | |
Monash University | |
Macquarie University | |
National Institute for Astrophysics, Italy | |
University of Sydney | |
University of Ljubljana, Slovenia | |
Centre for Astrophysics | |
Johns Hopkins University, United States | |
Institution of Origin | University of Southern Queensland |
https://research.usq.edu.au/item/q6z0y/the-galah-survey-chemical-tagging-and-chrono-chemodynamics-of-accreted-halo-stars-with-galah-dr3-and-gaia-edr3
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