The GALAH Survey: chemical tagging and chrono-chemodynamics of accreted halo stars with GALAH+ DR3 and Gaia eDR3

Buder, Sven and Lind, Karin and Ness, Melissa K. and Feuillet, Diane K. and Horta, Danny and Monty, Stephanie and Buck, Tobias and Nordlander, Thomas 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 Kos, Janez and Martell, Sarah L. and Lewis, Geraint F. and Lin, Jane and Schlesinger, Katharine J. and Sharma, Sanjib and Simpson, Jeffrey D. and Stello, Dennis and Zucker, Daniel B. and Zwitter, Tomaz and Ciuca, Ioana and Horner, Jonathan and Kobayashi, Chiaki and Ting, Yuan-Sen and Wyse, Rosemary F. G. (2022) The GALAH Survey: chemical tagging and chrono-chemodynamics of accreted halo stars with GALAH+ DR3 and Gaia eDR3. Monthly Notices of the Royal Astronomical Society, 510 (2). pp. 2407-2436. ISSN 0035-8711

[img]
Preview
Text (Published Version)
The GALAH Survey Chemical tagging and chrono-chemodynamics of.pdf

Download (5MB) | Preview

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.


Statistics for USQ ePrint 46132
Statistics for this ePrint Item
Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
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: 15 Feb 2022 03:34
Last Modified: 13 Apr 2022 23:46
Uncontrolled Keywords: The Galaxy; Galaxy: formation; Galaxy: halo; Galaxy: abundances; Galaxy: kinematics and dynamics; Astrophysics - Astrophysics of Galaxies; Astrophysics - Solar and Stellar Astrophysics
Fields of Research (2008): 02 Physical Sciences > 0201 Astronomical and Space Sciences > 020110 Stellar Astronomy and Planetary Systems
02 Physical Sciences > 0201 Astronomical and Space Sciences > 020104 Galactic Astronomy
Fields of Research (2020): 51 PHYSICAL SCIENCES > 5101 Astronomical sciences > 510104 Galactic astronomy
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/stab3504
URI: http://eprints.usq.edu.au/id/eprint/46132

Actions (login required)

View Item Archive Repository Staff Only