Risa Wechsler (U.Michigan)
"Consequences of Halo Assembly Histories for the Structure of Dark Matter Halos and Galaxies"


Using simulations of high enough resolution to simultaneously track halo assembly and the evolution of halo structural parameters for a statistical sample of halos, we show that halo mass accretion histories can be characterized by a universal form with one parameter, the formation scalefactor, which sets the concentration of halo density profiles, and accounts for the scatter, mass and redshift dependence of halo concentration. I discuss the effects of this correlation on predictions for galaxy structural parameters from semi-analytic modeling which, for the first time, include a relation between halo mass accretion histories and their density profiles, including the implication that halo concentration is correlated with galaxy type. These predictions are compared with observational measures of galaxy structure for a range of galaxy types.

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