Ciucă, Ioana;
Kawata, Daisuke;
Ting, Yuan-Sen;
Grand, Robert JJ;
Miglio, Andrea;
Hayden, Michael;
Baba, Junichi;
... Freeman, Ken; + view all
(2023)
Chasing the impact of the Gaia-Sausage-Enceladus merger on the formation of the Milky Way thick disc.
Monthly Notices of the Royal Astronomical Society: Letters
, Article slad033. 10.1093/mnrasl/slad033.
(In press).
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Abstract
We employ our Bayesian Machine Learning framework BINGO (Bayesian INference for Galactic archaeOlogy) to obtain high-quality stellar age estimates for 68,360 red giant and red clump stars present in the 17th data release of the Sloan Digital Sky Survey, the APOGEE-2 high-resolution spectroscopic survey. By examining the denoised age-metallicity relationship of the Galactic disc stars, we identify a drop in metallicity with an increase in [Mg/Fe] at an early epoch, followed by a chemical enrichment episode with increasing [Fe/H] and decreasing [Mg/Fe]. This result is congruent with the chemical evolution induced by an early-epoch gas-rich merger identified in the Milky Way-like zoom-in cosmological simulation Auriga. In the initial phase of the merger of Auriga 18 there is a drop in metallicity due to the merger diluting the metal content and an increase in the [Mg/Fe] of the primary galaxy. Our findings suggest that the last massive merger of our Galaxy, the Gaia-Sausage-Enceladus, was likely a significant gas-rich merger and induced a starburst, contributing to the chemical enrichment and building of the metal-rich part of the thick disc at an early epoch.
| Type: | Article |
|---|---|
| Title: | Chasing the impact of the Gaia-Sausage-Enceladus merger on the formation of the Milky Way thick disc |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1093/mnrasl/slad033 |
| Publisher version: | https://doi.org/10.1093/mnrasl/slad033 |
| Language: | English |
| Additional information: | This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions. |
| Keywords: | Galaxy: formation, Galaxy: abundances, asteroseismology |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Space and Climate Physics |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10168176 |
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