The DEEP2 Galaxy Redshift Survey: The red sequence AGN fraction and its environment and redshift dependence

Antonio D. Montero-Dorta, Darren J. Croton, Renbin Yan, Michael C. Cooper, Jeffery A. Newman, Antonis Georgakakis, Francisco Prada, Marc Davis, Kirpal Nandra, Alison Coil

Research output: Contribution to journalArticlepeer-review

25 Scopus citations


We measure the dependence of the active galactic nuclei (AGN) fraction on local environment at z ∼ 1, using spectroscopic data taken from the DEEP2 Galaxy Redshift Survey, and Chandra X-ray data from the All-Wavelength Extended Groth Strip International Survey (AEGIS). To provide a clean sample of AGN, we restrict our analysis to the red sequence population; this also reduces additional colour-environment correlations. We find evidence that high-redshift LINERs in DEEP2 tend to favour higher density environments relative to the red population from which they are drawn. In contrast, Seyferts and X-ray selected AGN at z ∼ 1 show little (or no) environmental dependencies within the same underlying population. We compare these results with a sample of local AGN drawn from the Sloan Digital Sky Survey (SDSS). Contrary to the high-redshift behaviour, we find that both LINERs and Seyferts in the SDSS show a slowly declining red sequence AGN fraction towards high-density environments. Interestingly, at z ∼ 1 red sequence Seyferts and LINERs are approximately equally abundant. By z ∼ 0, however, the red Seyfert population has declined relative to the LINER population by over a factor of ∼4.5. We speculate on possible interpretations of our results.

Original languageEnglish
Pages (from-to)125-134
Number of pages10
JournalMonthly Notices of the Royal Astronomical Society
Issue number1
StatePublished - Jan 2009


  • Galaxies: active
  • Galaxies: evolution
  • Galaxies: high-redshift
  • Galaxies: statistics
  • Large-scale structure of Universe

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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