PRIMUS: Constraints on Star Formation Quenching and Galaxy Merging, and the Evolution of the Stellar Mass Function from z = 0-1
Abstract
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 deg2, 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 ~1010 {M}_{\odot } galaxies since z ≈ 0.6, and a <~ 10% change in the number density of all >~ 1011 {M}_{\odot } 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 ~1010 {M}_{\odot } star-forming galaxies stays relatively constant since z ≈ 0.6, whereas the space density of >~ 1011 {M}_{\odot } star-forming galaxies decreases by ≈50% between z ≈ 1 and z ≈ 0. Meanwhile, the number density of ~1010 {M}_{\odot } quiescent galaxies increases steeply toward 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 ~1010.8 {M}_{\odot }. 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 (gsim 1011 {M}_{\odot }) quiescent galaxies.
- Publication:
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The Astrophysical Journal
- Pub Date:
- April 2013
- DOI:
- 10.1088/0004-637X/767/1/50
- arXiv:
- arXiv:1301.1688
- Bibcode:
- 2013ApJ...767...50M
- Keywords:
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- galaxies: evolution;
- galaxies: high-redshift;
- large-scale structure of universe;
- surveys;
- Astrophysics - Cosmology and Extragalactic Astrophysics
- E-Print:
- Published ApJ version with minor changes incorporated