The gemini cluster astrophysics spectroscopic survey (GCLASS): The role of environment and self-regulation in galaxy evolution at z ∼ 1

Adam Muzzin, Gillian Wilson, H. K.C. Yee, David Gilbank, Henk Hoekstra, Ricardo Demarco, Michael Balogh, Pieter Van Dokkum, Marijn Franx, Erica Ellingson, Amalia Hicks, Julie Nantais, Allison Noble, Mark Lacy, Chris Lidman, Alessandro Rettura, Jason Surace, Tracy Webb

Research output: Contribution to journalArticlepeer-review

202 Scopus citations

Abstract

We evaluate the effects of environment and stellar mass on galaxy properties at 0.85 <z < 1.20 using a 3.6 μm-selected spectroscopic sample of 797 cluster and field galaxies drawn from the Gemini Cluster Astrophysics Spectroscopic Survey. We confirm that for galaxies with logM */M > 9.3 the well-known correlations between environment and properties such as star-forming fraction (f SF), star formation rate (SFR), specific SFR (SSFR), D n(4000), and color are already in place at z ∼ 1. We separate the effects of environment and stellar mass on galaxies by comparing the properties of star-forming and quiescent galaxies at fixed environment and fixed stellar mass. The SSFR of star-forming galaxies at fixed environment is correlated with stellar mass; however, at fixed stellar mass it is independent of environment. The same trend exists for the D n(4000) measures of both the star-forming and quiescent galaxies and shows that their properties are determined primarily by their stellar mass, not by their environment. Instead, it appears that environment's primary role is to control the fraction of star-forming galaxies. Using the spectra we identify candidate poststarburst galaxies and find that those with 9.3 < logM */M < 10.7 are 3.1 ± 1.1 times more common in high-density regions compared to low-density regions. The clear association of poststarbursts with high-density regions as well as the lack of a correlation between the SSFRs and D n(4000)s of star-forming galaxies with their environment strongly suggests that at z 1 the environmental-quenching timescale must be rapid. Lastly, we construct a simple quenching model which demonstrates that the lack of a correlation between the D n(4000) of quiescent galaxies and their environment results naturally if self quenching dominates over environmental quenching at z > 1, or if the evolution of the self-quenching rate mirrors the evolution of the environmental-quenching rate at z > 1, regardless of which dominates.

Original languageEnglish (US)
Article number188
JournalAstrophysical Journal
Volume746
Issue number2
DOIs
StatePublished - Feb 20 2012

Keywords

  • galaxies: clusters: general
  • galaxies: evolution
  • galaxies: formation
  • galaxies: high-redshift

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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