In the last few years, the unparalleled wealth of data from the Gaia satellite allowed us to map unexplored regions of our Galaxy, revealing a large variety of features and complex stellar motions in the Galactic disc. In this talk, I will provide an overview of the most recent results on the three-dimensional morphology and large-scale kinematics of the Milky Way’s disc. I will present a new three-dimensional map based on young giant stars out to 8 kpc, whose in-plane distribution shows evidence of coherent spiral arm segments. The new segments extend previous maps based on OB stars by 2-4 kpc, improving our knowledge of the spiral structure of the Milky Way. The young giants exhibit a local vertical disc scale-height of 74 ± 5 pc, which progressively thickens toward the outer Galaxy with a prominent Galactic flare, rising exponentially with a radial scale length of 3.6 ± 0.1 kpc. We also report the detection of a large-scale vertical corrugation on top of the Galactic warp, with a vertical height of ∼150-200 pc, and a total in-plane length of at least 10 kpc (possibly reaching 20 kpc with classical Cepheids). The comparison of the observed velocities with a simple toy model suggests that the corrugation can be interpreted as a large-scale Galactic wave propagating towards the outer disc. Finally, I will highlight the major open questions and discuss how future datasets will help tackle them.
The Milky Way through Gaia’s eyes : morphology and kinematics of the Galactic disc
Mardi 8 septembre 2026
de
14:00 à
15:00
Room 108, Les Communs
