Rediscovering the Milky Way with an orbit superposition approach and APOGEE data
Year: 2025
Type: article
Abstract: Context . The Milky Way’s (MW’s) star formation history (SFH) offers insights into the chronology of its assembly and the mechanisms driving its structural development. Aims . In this study, we present an inference and analysis of the spatially resolved SFH and the MW disc growth. Methods . Our approach leverages both stellar birth radii estimates and the complete reconstruction of the MW stellar disc using a novel orbit superposition method from APOGEE data, allowing us to trace the orbit-mass weighted SFH based on formation sites, while taking into account stellar mass loss. Results . We find that the MW is a typical disc galaxy exhibiting inside-out formation: it was compact at z > 2 (R eff ≈ 2 kpc), had a peak in its star formation rate (SFR) 9–10 Gyr ago, and grew to a present-day size of R eff ≈ 4.3 kpc. A secondary peak in the SFR ~4 Gyr ago is responsible for the onset of the outer disc, which comprises the metal-poor, low- α population. We find that in situ star formation in the solar neighbourhood started 8–9 Gyr ago. The MW disc is characterised by a negative mean age gradient, as the result of the inside-out growth, with additional flattening induced by stellar radial migration. Conclusions . Our work showcases the importance of accounting for radial migration and the stellar sample selection function when inferring the SFH and build-up of the MW disc.
Source: Astronomy and Astrophysics
Authors: Bridget Ratcliffe, Sergey Khoperskov, Nathan Lee, Ivan Minchev, Paola Di Matteo, Glenn van de Ven, Misha Haywood, Léa Marques, John Paul Bernaldez, Davor Krajnović, Matthias Steinmetz
Institutions: Leibniz Institute for Astrophysics Potsdam, University of Vienna, Berlin Institute for the Foundations of Learning and Data, Centre National de la Recherche Scientifique, Université Paris Cité, Université Paris Sciences et Lettres, Observatoire de Paris, Sorbonne Université, CY Cergy Paris Université, University of Potsdam, Friedrich Schiller University Jena
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,865
Funders: Smithsonian Institution, U.S. Department of Energy, Alfred P. Sloan Foundation, Yale University, Carnegie Institution of Washington, Vanderbilt University, Ohio State University, University of Utah, University of Washington, Johns Hopkins University, Carnegie Mellon University, University of Notre Dame, University of Portsmouth, New Mexico State University, European Space Agency, York University, University of Oxford, Deutsche Forschungsgemeinschaft, Universität Wien, Ministério da Ciência, Tecnologia e Inovação, Universidad Nacional Autónoma de México, Max-Planck-Institut für Astrophysik, Max-Planck-Institut für Astronomie, Instituto de Astrofísica de Canarias, Office of Science, University of Colorado Boulder, Leibniz-Gemeinschaft, Lawrence Berkeley National Laboratory
OpenAlex ID: W4417283256