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Title

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

Author(s)

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

Abstract

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.

Publication type

Journal article

Source

Monthly Notices of the Royal Astronomical Society, Vol. 392, no. 1 (Jan 2009), pp. 125-134

Publication year

2009

FOR Code(s)

0201 Astronomical and Space Sciences

Keyword(s)

Active galactic nuclei;  Active galaxies;  Galaxy evolution;  High-redshift

Publisher

Wiley-Blackwell Publishing

ISSN

0035-8711

Publisher URL

http://dx.doi.org/10.1111/j.1365-2966.2008.13893.x

Copyright

Copyright © 2009 The Authors. Journal compilation copyright © 2009 Royal Astronomical Society. Accepted manuscript reproduced here in accordance with the copyright policy of the publisher. The definitive publication is available at www.interscience.wiley.com.

Full text

Peer reviewed