I will explain how to use the motions of stars to learn about the nature of particles. More specifically, I will translate the stellar kinematics that I observe in the nearest, smallest and `darkest’ galaxies into a test of the standard hypothesis that dark matter consists of `cold’ and `collisionless’ (i.e., weakly interacting) particles. This model escapes falsification only if baryon-driven processes (e.g., energetic feedback from supernova explosions) can alter the internal structure of galactic dark matter halos systematically with respect to predictions derived from cosmological N-body simulations. I will identify future work, both observational and theoretical, that I expect will tell definitively whether such reconciliation is energetically feasible or whether the dark matter model requires additional complexity.
MP 102
Matthew Walker (Harvard)
February 04, 2013
15:00 - 16:00