Joint Astrophysics Colloquium

Triumphs and tribulations of near-field cosmology with wide-field surveys: a biased perspective

Beth Willman

Haverford

Over the last decade, wide-field surveys have revolutionized our view of the Milky Way's stellar halo and dwarf galaxy population. Much of this observational progress has been motivated by a series of apparent ‘crises’ for our cosmological model: the missing satellites problem, too big to fail, and the apparent planar distribution of dwarf satellite galaxies. These challenges have effectively functioned as flashlights pointing us to interesting galaxy formation physics. I will highlight related observational progress in our understanding of galaxy formation using near-field observations. I will then focus on the limiting impacts of observational bias and ways that current and future surveys will be used to tackle these biases. In particular, I will present new predictions for the number of Milky Way dwarf galaxies expected to be discovered in DES and LSST, RR Lyrae stars as a tool to discover dwarf galaxies in previously unexplored territory, and the use of M giant stars to map the Milky Way's halo beyond its virial radius