John Moustakas, Alison Coil, James Aird, Michael R. Blanton, Richard J. Cool, Daniel J. Eisenstein, Alexander J. Mendez, Kenneth C. Wong, Guangtun Zhu, Stephane Arnouts
We measure the evolution of the stellar mass function (SMF) from z=0-1 using multi-wavelength imaging and spectroscopic redshifts from the PRism MUlti-object Survey (PRIMUS) and the Sloan Digital Sky Survey (SDSS). From PRIMUS we construct an i<23 flux-limited sample of ~40,000 galaxies at z=0.2-1.0 over five fields totaling ~5.5 deg^2, and from the SDSS we select ~170,000 galaxies at z=0.01-0.2 that we analyze consistently with respect to PRIMUS to minimize systematic errors in our evolutionary measurements. We find that the SMF of all galaxies evolves relatively little since z=1, although we do find evidence for mass assembly downsizing; we measure a ~30% increase in the number density of ~10^10 Msun galaxies since z~0.6, and a <10% change in the number density of all >10^11 Msun galaxies since z~1. Dividing the sample into star-forming and quiescent using an evolving cut in specific star-formation rate, we find that the number density of ~10^10 Msun star-forming galaxies stays relatively constant since z~0.6, whereas the space-density of >10^11 Msun star-forming galaxies decreases by ~50% between z~1 and z~0. Meanwhile, the number density of ~10^10 Msun quiescent galaxies increases steeply towards low redshift, by a factor of ~2-3 since z~0.6, while the number of massive quiescent galaxies remains approximately constant since z~1. These results suggest that the rate at which star-forming galaxies are quenched increases with decreasing stellar mass, but that the bulk of the stellar mass buildup within the quiescent population occurs around ~10^10.8 Msun. In addition, we conclude that mergers do not appear to be a dominant channel for the stellar mass buildup of galaxies at z<1, even among massive (>10^11 Msun) quiescent galaxies.
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http://arxiv.org/abs/1301.1688
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