A fundamental goal in observational cosmology is to understand the link between the luminous properties of galaxies and the dark matter halos in which they reside. Because this link is fundamental to processes that determine the growth, evolution, and global properties of galaxies, key insight can be gained by mapping how the distributions of dark and luminous matter vary across different scales and over cosmic time.
In this talk I will discuss new methods to probe the galaxy-halo connection from galaxy scales (tens of kpc to 100 kpc) out to the scale of dark matter halos, themselves (hundreds of kpc to a Mpc). On the smallest scales, I will show that novel weak lensing techniques applied to upcoming surveys such as WFIRST and Euclid can map the inner density profiles of galaxies and provide strong constraints on the inner slope of dark matter as well as the stellar IMF.
In the second half of the talk I will shift to the largest scales where a combination of probes provides insight about how galaxies grow (or do not grow) in relation to their global reservoirs of fuel. In particular, I will present a new, comprehensive framework that describes how the most massive galaxies populate dark matter halos and how their colors may be determined by their halo assembly history. Even before more powerful constraints from future surveys, I will show how such models combined with state-of the art measurements of weak gravitational lensing and galaxy clustering from the CS82 and BOSS surveys are already yielding surprising discoveries.
