CCA Colloquium: Risa Wechsler

Title: Our Galaxy in Context: Clues to the nature of dark matter, the onset of galaxy formation, and the assembly history of the Milky Way.

Abstract: We are in the midst of a revolution in understanding our own galaxy and its cosmological context, driven by discoveries of dozens of new ultra faint galaxies in the Milky Way system, measurements of the Milky Way’s dynamics, and the characterization of Milky Way-like systems and their satellites well outside the Local Group. I will discuss new observational results on satellite galaxies within the Milky Way and similar nearby systems and describe what those measurements imply about the dark matter halos that host the smallest galaxies. I will then discuss how these measurements help place our own Galaxy and its assembly history in its broader cosmological context and how they provide clues to the formation of the first galaxies and new limits on a range of possibilities for the microphysical properties of the dark matter that dominates our Universe.