Abstract

The release of high-precision astrometric data from the Gaia space mission has revolutionized studies of the Milky Way’s halo substructures over the past few years. I have used this data to model the dynamics of Milky Way satellite galaxies, globular clusters, stellar streams, and the stellar halo, often by incorporating comparisons to cosmological simulations that include galaxy formation. The Milky Way satellite galaxies have tangentially dominated motions, a kinematic signature consistent with the central galaxy disrupting radial orbits that pass nearby. Using updated catalogs of globular cluster phase-space measurements and new stellar stream discoveries, I will show that these substructures are not aligned with the Milky Way’s plane of satellite galaxies, suggesting this unusual orbital configuration in LCDM is not a long-lived structure or the result of a recent accretion event. Additionally, I will show that substructures in simulated stellar halos can produce velocity dipoles along the sky, complicating recent findings that attribute a similar signal in the Milky Way halo to the LMC. Finally, I will describe how we can develop simulation and modeling infrastructure to properly leverage observations from upcoming facilities in the next generation of Local Group dynamical studies.