Abstract

We are currently witnessing a golden age in Galactic halo science. Largely thanks to the Gaia mission, we now have phase-space plus chemical information for significant numbers of halo stars, globular clusters and satellite dwarf galaxies in the Milky Way. These halo populations can be used to uncover the assembly history of the Galaxy, probe the nature of dark matter, and scrutinise cosmological models. In this talk I will describe recent efforts to address these fundamental questions using a combination of new observational data and state-of-the-art cosmological simulations. In particular, I will discuss the total mass and mass profile of the Milky Way, the last major accretion event that shaped the Galaxy’s history, and the (surviving and destroyed) dwarf satellite luminosity function.