Abstract:

Stellar streams provide a record of their host’s merger history and the opportunity to study stellar populations of older, disrupting galaxies. As more of these structures have been uncovered in wide-area digital sky surveys, there has been a push to characterize the full system of tidally disrupting satellites in simulations at Milky Way-mass and smaller scales. I will present my efforts to do so in two regimes: fully hydrodynamical simulations (Auriga) and “painting” stars onto the highest resolution cosmological simulation ever run of a Milky Way-mass halo (Aquarius). These simulations predict that (i) most satellites are disrupting to form faint tidal streams, (ii) many of these streams are detectable in Rubin/LSST-depth photometry, and (iii) most Milky Way satellites have their own accreted stellar haloes formed from mergers with smaller galaxies. These results suggest that upcoming surveys (DESI, Rubin LSST, Arrakihs) will unlock new tests of dark matter and hierarchical galaxy formation at the smallest scales.