Abstract: Galaxies form as gas cools and condenses onto halos of dark matter. Baryons composing the observable parts of galaxies are influenced by dark matter through gravitational interactions. Thus, the motions of stars in galaxies are governed by the baryonic and dark matter content. Stellar velocity dispersion is an observable property directly connecting the baryonic content of galaxies to the unobserved dark matter halo. I will discuss our program to use velocity dispersions as a tool for understanding the dynamical properties of quiescent galaxies and for constraining their evolution. Our results suggest that quiescent galaxies are in approximate virial equilibrium and that the stellar velocity dispersion may be the best observable to connect galaxies to their dark matter halo. I will discuss how these observations may be used to constrain simulations.

Host: Paul Torrey