DARK MATTER HALO MODELS OF STELLAR MASS-DEPENDENT GALAXY CLUSTERING IN PRIMUS+DEEP2 AT 0.2 < z < 1.2

Abstract

We utilize ΛCDM halo occupation models of galaxy clustering to investigate the evolving stellar mass dependent clustering of galaxies in the PRIsm MUlti-object Survey (PRIMUS) and DEEP2 Redshift Survey over the past eight billion years of cosmic time, between 0.2 < z < 1.2. These clustering measurements provide new constraints on the connections between dark matter halo properties and galaxy properties in the context of the evolving largescale structure of the universe. Using both an analytic model and a set of mock galaxy catalogs, we find a strong correlation between central galaxy stellar mass and dark matter halo mass over the range Mhalo ∼ 10111013 h-1 M⊙, approximately consistent with previous observations and theoretical predictions. However, the stellarto-halo mass relation and the mass scale where star formation efficiency reaches a maximum appear to evolve more strongly than predicted by other models, including models based primarily on abundance-matching constraints. We find that the fraction of satellite galaxies in halos of a given mass decreases significantly from z ∼ 0.5 to z ∼ 0.9, partly due to the fact that halos at fixed mass are rarer at higher redshift and have lower abundances. We also find that the M1/Mmin ratio, a model parameter that quantifies the critical mass above which halos host at least one satellite, decreases from ≈20 at z ∼ 0 to ≈13 at z ∼ 0.9. Considering the evolution of the subhalo mass function vis-à-vis satellite abundances, this trend has implications for relations between satellite galaxies and halo substructures and for intracluster mass, which we argue has grown due to stripped and disrupted satellites between z ∼ 0.9 and z ∼ 0.5.