Journal
ASTRONOMY & ASTROPHYSICS
Volume 655, Issue -, Pages -Publisher
EDP SCIENCES S A
DOI: 10.1051/0004-6361/202140453
Keywords
Galaxy: disk; Galaxy: evolution; Galaxy: abundances
Categories
Funding
- Alfred P. Sloan Foundation
- US Department of Energy Office of Science
- Center for High Performance Computing at the University of Utah
- Brazilian Participation Group
- Carnegie Institution for Science
- Carnegie Mellon University
- Center for Astrophysics
- Harvard Smithsonian
- Chilean Participation Group
- French Participation Group
- Instituto de Astrofisica de Canarias
- Johns Hopkins University
- Kavli Institute for the Physics and Mathematics of the Universe (IPMU)/University of Tokyo
- Korean Participation Group
- Lawrence Berkeley National Laboratory
- Leibniz Institut fur Astrophysik Potsdam (AIP)
- Max-Planck-Institut fur Astronomie (MPIA Heidelberg)
- Max-Planck-Institut fur Astrophysik (MPA Garching)
- Max-Planck-Institut fur Extraterrestrische Physik (MPE)
- National Astronomical Observatories of China
- New Mexico State University
- New York University
- University of Notre Dame
- Observatario Nacional/MCTI
- Ohio State University
- Pennsylvania State University
- Shanghai Astronomical Observatory
- United Kingdom Participation Group
- Universidad Nacional Autonoma de Mexico
- University of Arizona
- University of Colorado Boulder
- University of Oxford
- University of Portsmouth
- University of Utah
- University of Virginia
- University of Washington
- University of Wisconsin
- Vanderbilt University
- Yale University
- DIM ACAV+
Ask authors/readers for more resources
The debate on the formation of the Galactic disc continues, with studies focusing on processes such as satellite accretion, starburst, quenching, gas infall, and stellar radial migration. By analyzing data from the SDSS DR16 APOGEE catalogue and APOGEE-AstroNN Value Added Catalogue, researchers found evidence of inside-out formation in the Galactic thin disc up to a certain radius, with the outer disc showing higher magnesium-to-iron ratio compared to the inner regions, possibly due to pollution from the thick disc during its starburst phase approximately 7 billion years ago.
Context. The formation of the Galactic disc is an enthusiastically debated issue. Numerous studies and models seek to identify the dominant physical process(es) that shaped its observed properties; for example, satellite accretion, starburst, quenching, gas infall, and stellar radial migration. Aims. Taking advantage of the improved coverage of the inner Milky Way provided by the SDSS DR16 APOGEE catalogue and of the ages published in the APOGEE-AstroNN Value Added Catalogue (VAC), we examined the radial evolution of the chemical and age properties of the Galactic stellar disc with the aim of better constraining its formation. Methods. Using a sample of 199 307 giant stars with precise APOGEE abundances and APOGEE-AstroNN ages, selected in a +/- 2 kpc layer around the galactic plane, we assessed the dependency as a function of guiding radius of (i) the median metallicity, (ii) the ridge lines of the [Fe/H] - [Mg/Fe] and age-[Mg/Fe] distributions, and (iii) the age distribution function (ADF). Results. The giant star sample allows us to probe the radial behaviour of the Galactic disc from R-g = 0 to 14-16 kpc. The thick disc [Fe/H] - [Mg/Fe] ridge lines follow closely grouped parallel paths, supporting the idea that the thick disc did form from a well-mixed medium. However, the ridge lines present a small drift in [Mg/Fe], which decreases with increasing guiding radius. At sub-solar metallicity, the intermediate and outer thin disc [Fe/H] - [Mg/Fe] ridge lines follow parallel sequences shifted to lower metallicity as the guiding radius increases. We interpret this pattern as the signature of a dilution of the interstellar medium from R-g similar to 6 kpc to the outskirts of the disc, which occurred before the onset of the thin disc formation. The APOGEE-AstroNN VAC provides stellar ages for statistically significant samples of thin disc stars from the Galactic centre up to R-g similar to 14 kpc. An important result provided by this dataset is that the thin disc presents evidence of an inside-out formation up to R-g similar to 10-12 kpc. Moreover, about similar to 7 Gyr ago, the [Mg/Fe] ratio in the outer thin disc (R-g > 10 kpc) was higher by about similar to 0.03-0.05 dex than in the more internal regions of the thin disc. This could be the fossil record of a pollution of the outer disc gas reservoir by the thick disc during its starburst phase.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available