Speaker
Description
I will present how the improvement in astrometry provided by Gaia-NIR for stars in the outermost component of our Galaxy, the stellar halo, will allow us to better constrain the formation history of the Milky Way and the distribution of dark matter. In recent years, several studies have shown that the halo is out of equilibrium and strongly perturbed, in particular due to the infall of the Large Magellanic Cloud. Understanding these perturbations requires high-precision six-dimensional phase-space information of halo stars, which Gaia-NIR will deliver. I will also show how Gaia-NIR will improve the study of stellar streams, both in the halo and the disc. These streams can be used to anchor the Galactic potential, probe its granularity, and reveal the population of dark matter subhaloes orbiting our Galaxy. In the disc, the near-infrared data will make it possible to trace streams from disrupted open clusters, providing constraints on the evolution of the bar and spiral arms, as well as on streams passing near the Galactic center, offering a more complete 3D view of the Milky Way’s mass distribution.
