Testing Galaxy Formation Models with Large-scale Surveys of the Milky Way Stellar Halo

Speaker Emily Cunningham (CCA)

May 16, 2022

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Abstract: While the vast majority of the light from our Galaxy comes from the Galactic disk, the vast majority of the mass of the Milky Way (MW) is in its dark matter halo. Because we cannot directly observe the MW’s dark matter halo, we must use luminous tracer populations to study the mass distribution indirectly. Fortunately, there are stars strewn throughout the MW’s dark matter halo. According to the hierarchical paradigm for galaxy evolution, the MW built up its halo of dark matter over cosmic time by accreting smaller dwarf galaxies. The remnants of these accreted dwarfs make up the MW’s stellar halo. Halo stars can therefore be used both to constrain the dark matter distribution of the MW as well as inform us about the dwarf galaxies in which they formed. I will present my ongoing theoretical and observational work using halo stars to map the dark matter distribution and disequilibrium in the MW, as well as study the faint, low-mass galaxies that were consumed by the MW during its formation. I will discuss the crucial roles of current and upcoming large-scale surveys of the MW halo for addressing fundamental questions in galaxy formation.