The deep2 galaxy redshift survey: Clustering dependence on galaxy stellar mass and star formation rate at z ∼ 1

Abstract

We present DEEP2 galaxy clustering measurements at z ∼ 1 as a function of stellar mass, star formation rate (SFR), and specific SFR (sSFR). We find a strong positive correlation between stellar mass and clustering amplitude on 1-10 h -1 Mpc scales for blue, star-forming galaxies with 9.5 < 11 and no dependence for red, quiescent galaxies with 10.5 < 11.5. Using recently re-calibrated DEEP2 SFRs from restframe B-band magnitude and optical colors, we find that within the blue galaxy population at z ∼ 1 the clustering amplitude increases strongly with increasing SFR and decreasing sSFR. For red galaxies there is no significant correlation between clustering amplitude and either SFR or sSFR. Blue galaxies with high SFR or low sSFR are as clustered on large scales as red galaxies. We find that the clustering trend observed with SFR can be explained mostly, but not entirely, by the correlation between stellar mass and clustering amplitude for blue galaxies. We also show that galaxies above the star-forming "main sequence" are less clustered than galaxies below the main sequence, at a given stellar mass. These results are not consistent with the high-sSFR population being dominated by major mergers. We also measure the clustering amplitude on small scales (≤0.3 h -1 Mpc) and find an enhanced clustering signal relative to the best-fit large-scale power law for red galaxies with high stellar mass, blue galaxies with high SFR, and both red and blue galaxies with high sSFR. The increased small-scale clustering for galaxies with high sSFRs is likely linked to triggered star formation in interacting galaxies. These measurements provide strong constraints on galaxy evolution and halo occupation distribution models at z ∼ 1. © 2013. The American Astronomical Society. All rights reserved.