“Formation the Milky Way’s inner stellar halo and disc: insights from numerical simulations and observations”
In this talk I will present recent results regarding the formation history of the Milky Way’s stellar halo and disc. Gaia has conclusively shown that the inner stellar halo is dominated by highly anisotropic debris suggesting that the Galaxy underwent an ancient merger with another galaxy in its distant past somewhere around z~2. How massive was this merger? When did it happen? What were the repercussions of this event for the formation of the stellar halo? Did this merger have any impact on the formation and later evolution of the disc? I will explore and try to answer these questions using a combination of clues/constraints we have from the observations of our own Milky Way as well as predictions from numerical hydrodynamical models of the formation and evolution of Milky Way-like galaxies considering both idealised experiments as well as cosmological ones.