Structure and dynamics of the Galactic stellar halo

The Milky Way is a unique testbed for theories of galaxy formation and evolution. Especially the stellar halo is amenable to studies into our galaxy’s past both because it contains some of the oldest stars and because the dynamical timescales are long. The most recent development in the field is the realization of the level of interconnectedness of all the components of the Milky Way — and the interactions with neighboring satellite galaxies. In this talk, I will discuss some of my latest results on the structure of the Milky Way’s halo and place these in the context of these recent developments. One of these results is the selection method of a large sample of halo stars from the Gaia 5D data set (without line-of-sight velocities). I used this sample to determine the escape velocity of the Milky Way at the location of the Sun, which is a direct measurement of the galactic potential. Furthermore, I will discuss a method to calculate the evolution of gaps in cold stellar streams that are created by interactions with dark matter subhalos. And, finally, I will show a result that not all structures in dynamical spaces (e.g. orbital frequency space) are related to interactions and or to the merger history of the Milky Way.



The Institute for Advanced Study