The Evolving Luminosity Function of Red Galaxies

Abstract

We trace the assembly history of red galaxies since z=1, by measuring their evolving space density with the B-band luminosity function. Our sample of 39599 red galaxies, selected from 6.96 square degrees of imaging from the NOAO Deep Wide-Field and Spitzer IRAC Shallow surveys, is an order of magnitude larger, in size and volume, than comparable samples in the literature. We measure a higher space density of z=0.9 red galaxies than some of the recent literature, in part because we account for the faint yet significant galaxy flux which falls outside of our photometric aperture. The B-band luminosity density of red galaxies, which effectively measures the evolution of ~L* galaxies, increases by only 36 percent from z=0 to z=1. If red galaxy stellar populations have faded by 1.24 B-band magnitudes since z=1, the stellar mass contained within the red galaxy population has roughly doubled over the past 8 Gyr. This is consistent with star-forming galaxies being transformed into ~L* red galaxies after a decline in their star formation rates. In contrast, the evolution of 4L* red galaxies differs only slightly from a model with negligible star formation and no galaxy mergers since z=1. If this model approximates the luminosity evolution of red galaxy stellar populations, then 80 percent of the stellar mass contained within today's 4L* red galaxies was already in place at z=0.7. While red galaxy mergers have been observed, such mergers do not produce rapid growth of 4L* red galaxy stellar masses between z=1 and the present day.Comment: Accepted for publication in the ApJ. 30 pages, 18 figures. (Several typos corrected and slight change to Figure 8.

Evolution of the early-type galaxy fraction in clusters since z = 0.8

“…Poggianti et al (2006) proposed a scenario in which two channels are responsible for the production of passive galaxies in clusters, and others (Faber et al 2007;Brown et al 2007) have proposed a similar scenario for the migration of galaxies from the "blue cloud" to the red sequence. "Primordial passive galaxies" are composed of galaxies whose stars all formed at very high redshift (z > 2) over a short timescale.…”

The Spitzer Extragalactic Representative Volume Survey (SERVS): Survey Definition and Goals*

“…Galaxies detected in SERVS will therefore span the epochs where galaxies gain the vast majority of their stellar mass. Indeed, Brown et al (2007) and Cool et al (2008) estimate that L Ã galaxies roughly double in mass between z ¼ 0 and z ≈ 1. In addition, van Dokkum et al (2010) recently showed that about half the mass of any given large galaxy is added between z ¼ 0 and z ¼ 2, by comparing galaxy samples at constant number densities.…”

Star formation in the intragroup medium and other diagnostics of the evolutionary stages of compact groups of galaxies

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