LINKING GALAXIES TO DARK MATTER HALOS AT z ∼ 1: DEPENDENCE OF GALAXY CLUSTERING ON STELLAR MASS AND SPECIFIC STAR FORMATION RATE

Abstract

We study the dependence of angular two-point correlation functions on stellar mass (M∗) and specific star formation rate (sSFR) of M∗ > 1010M⊙ galaxies at z ∼ 1. The data from the UK Infrared Telescope Infrared Deep Sky Survey Deep eXtragalactic Survey and Canada-France-Hawaii Telescope Legacy Survey cover 8.2 deg2 sample scales larger than 100 h-1 Mpc at z ∼ 1, allowing us to investigate the correlation between clustering, M∗, and star formation through halo modeling. Based on halo occupation distributions (HODs) of M∗ threshold samples, we derive HODs for M∗ binned galaxies, and then calculate the M∗/Mhalo ratio. The ratio for central galaxies shows a peak at Mhalo ∼ 1012h-1M⊙, and satellites predominantly contribute to the total stellar mass in cluster environments with M∗/Mhalo values of 0.01-0.02. Using star-forming galaxies split by sSFR, we find that main sequence galaxies (log sSFR/yr-1 ∼ -9) are mainly central galaxies in ∼ 1012.5h-1M⊙ halos with the lowest clustering amplitude, while lower sSFR galaxies consist of a mixture of both central and satellite galaxies where those with the lowest M∗ are predominantly satellites influenced by their environment. Considering the lowest Mhalo samples in each M∗ bin, massive central galaxies reside in more massive halos with lower sSFRs than low mass ones, indicating star-forming central galaxies evolve from a low M∗-high sSFR to a high M∗-low sSFR regime. We also find that the most rapidly star-forming galaxies (log sSFR/yr-1 > -8.5) are in more massive halos than main sequence ones, possibly implying galaxy mergers in dense environments are driving the active star formation. These results support the conclusion that the majority of star-forming galaxies follow secular evolution through the sustained but decreasing formation of stars.