The clustering and halo masses of star-forming galaxies at z < 1

Abstract

We present clustering measurements and halo masses of star-forming galaxies at 0.2 < z < 1.0. After excluding active galactic nuclei (AGNs), we construct a sample of 22,553 24 μm sources selected from 8.42 deg2 of the Spitzer MIPS AGN and Galaxy Evolution Survey of Boötes. Mid-infrared imaging allows us to observe galaxies with the highest star formation rates (SFRs), less biased by dust obscuration afflicting the optical bands. We find that the galaxies with the highest SFRs have optical colors that are redder than typical blue cloud galaxies, with many residing within the green valley. At z > 0.4 our sample is dominated by luminous infrared galaxies (LIRGs, LTIR > 1011 L⊙) and is composed entirely of LIRGs and ultraluminous infrared galaxies (ULIRGs, LTIR > 1012 L⊙) at z > 0.6. We observe weak clustering of r0 ≈ 3-6 h-1 Mpc for almost all of our star-forming samples. We find that the clustering and halo mass depend on LTIR at all redshifts, where galaxies with higher LTIR (hence higher SFRs) have stronger clustering. Galaxies with the highest SFRs at each redshift typically reside within dark matter halos of Mhalo ≈ 1012.9 h-1 M⊙. This is consistent with a transitional halo mass, above which star formation is largely truncated, although we cannot exclude that ULIRGs reside within higher mass halos. By modeling the clustering evolution of halos, we connect our star-forming galaxy samples to their local descendants. Most star-forming galaxies at z < 1.0 are the progenitors of L ≲ 2.5L∗ blue galaxies in the local universe, but star-forming galaxies with the highest SFRs (LTIR ≳ 1011.7 L⊙) at 0.6 < z < 1.0 are the progenitors of early-type galaxies in denser group environments.