The Concentration Dependence of the Galaxy-Halo Connection: Modeling
  Assembly Bias with Abundance Matching
  Empirical methods for connecting galaxies to their dark matter halos have
become essential for interpreting measurements of the spatial statistics of
galaxies. In this work, we present a novel approach for parameterizing the
degree of concentration dependence in the abundance matching method. This new
parameterization provides a smooth interpolation between two commonly used
matching proxies: the peak halo mass and the peak halo maximal circular
velocity. This parameterization controls the amount of dependence of galaxy
luminosity on halo concentration at a fixed halo mass. Effectively this
interpolation scheme enables abundance matching models to have adjustable
assembly bias in the resulting galaxy catalogs. With the new 400 Mpc/h DarkSky
Simulation, whose larger volume provides lower sample variance, we further show
that low-redshift two-point clustering and satellite fraction measurements from
SDSS can already provide a joint constraint on this concentration dependence
and the scatter within the abundance matching framework.
