Gaia mission data reveals a re-ignition of star formation in the Milky Way's disc about 5 billion years ago

R. Mor , A. C. Robin (1) , F. Figueras , X. Luri , T. Antoja , S. Roca-Fàbrega

1 UTINAM - Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213)

We use Gaia DR2 and the Besançon Galaxy model to simultaneously infer the initial mass function (IMF) and the star formation history of the Galactic disc. Our results show a decreasing trend of the SFR from 9-10 Gyr to 6-7 Gyr and a re-ignition starting at ∼5 Gyr ago and continuing until ∼1 Gyr ago. The timescale and the amount of stellar mass generated during the Star Formation Rate enhancement event lead us to hypothesise that its origin, currently under investigation, is not intrinsic to the disc. We hypothesise that an external perturbation is needed for its explanation.

Domaines: Astrophysique [astro-ph]

R. Mor, A. C. Robin, F. Figueras, X. Luri, T. Antoja, et al.. Gaia mission data reveals a re-ignition of star formation in the Milky Way's disc about 5 billion years ago. XIV.0 Scientific Meeting (virtual) of the Spanish Astronomical Society, Jul 2020, (virtuel), Spain. ⟨hal-03041150⟩