Giovedì 2 marzo alle ore 15:00, la Prof. Carmen Gallart dell’Instituto de Astrofísica de Canarias di Tenerife, Spagna, terrà il web-seminar dal titolo “The evolutionary history of the Milky Way disk(s) and halo from Gaia color-magnitude diagram fitting“.

Abstract

Gaia has provided distances and photometry, and thus color-magnitude diagrams in the absolute plane, for stars over an
unprecedented vast volume in the Milky Way, encompassing significant fractions of the thin and thick disk, and halo. This has allowed us, for the first time, to derive unprecedentedly detailed star formation histories from direct modelling of these color-magnitude diagrams, using the same techniques that have been proven successful for external galaxies in the
Local Group. Our first results for a volume of 2 Kpc radius from the Sun using Gaia DR2 were extraordinarily promising and allowed us to date the first events involved in the formation of the inner Milky Way halo (Gallart et al. 2019) and to determine the presence of epochs of enhanced star formation well constrained in time, that can be associated to the various pericentric passages of the Sagittarius dwarf galaxy (Ruiz-Lara et al. 2020). We are now studying, using Gaia DR3, the first spatially-resolved star formation histories for the Milky Way disk. They have been obtained by slicing, parallel to the plane, a cylinder spanning 1 Kpc heliocentric radius and ±3 Kpc height from the plane. These star formation histories across the Milky Way thin and thick disks show that distinct star formation episodes contribute differently at different heights above the plane, thus providing clear insights about the formation process of our Galactic disk.