Sign on

SAO/NASA ADS Astronomy Abstract Service

· Find Similar Abstracts (with default settings below)
· Electronic Refereed Journal Article (HTML)
· Full Refereed Journal Article (PDF/Postscript)
· arXiv e-print (arXiv:0807.2240)
· References in the article
· Citations to the Article (7) (Citation History)
· Refereed Citations to the Article
· SIMBAD Objects (2)
· Also-Read Articles (Reads History)
·
· Translate This Page
Title:
X-ray selected AGN in groups at redshifts z ~ 1
Authors:
Georgakakis, A.; Gerke, Brian F.; Nandra, K.; Laird, E. S.; Coil, A. L.; Cooper, M. C.; Newman, J. A.
Affiliation:
AA(Astrophysics Group, Blackett Laboratory, Imperial College, Prince Consort Rd, London SW7 2BZ; National Observatory of Athens, I. Metaxa & V. Paulou, Athens 15236, Greece), AB(Kavli Institute for Particle Astrophysics and Cosmology, Stanford Linear Accelerator Centre, 25 Sand Hill Rd. MS 29, Menlo Park, CA 94725, USA), AC(Astrophysics Group, Blackett Laboratory, Imperial College, Prince Consort Rd, London SW7 2BZ), AD(Astrophysics Group, Blackett Laboratory, Imperial College, Prince Consort Rd, London SW7 2BZ), AE(Steward Observatory, University of Arizona, 933 N. Cherry Ave., Tucson, AZ 85721-0065, USA), AF(Steward Observatory, University of Arizona, 933 N. Cherry Ave., Tucson, AZ 85721-0065, USA), AG(University of Pittsburgh, Physics & Astronomy Department, 3941 O'Hara Street Pittsburgh, PA 15260, USA)
Publication:
Monthly Notices of the Royal Astronomical Society, Volume 391, Issue 1, pp. 183-189. (MNRAS Homepage)
Publication Date:
11/2008
Origin:
MNRAS
MNRAS Keywords:
surveys , galaxies: active , galaxies: structure , large-scale structure of the Universe
DOI:
10.1111/j.1365-2966.2008.13649.x
Bibliographic Code:
2008MNRAS.391..183G

Abstract

We explore the role of the group environment in the evolution of active galactic nuclei (AGN) at the redshift interval 0.7 < z < 1.4, by combining deep Chandra observations with extensive optical spectroscopy from the All-wavelength Extended Groth strip International Survey (AEGIS). The sample consists of 3902 optical sources and 71 X-ray AGN. Compared to the overall optically selected galaxy population, X-ray AGN are more frequently found in groups at the 99 per cent confidence level. This is partly because AGN are hosted by red luminous galaxies, which are known to reside, on average, in dense environments. Relative to these sources, the excess of X-ray AGN in groups is significant at the 91 per cent level only. Restricting the sample to 0.7 < z < 0.9 and MB < -20mag in order to control systematics, we find that X-ray AGN represent (4.7 +/- 1.6) and (4.5 +/- 1.0) per cent of the optical galaxy population in groups and in the field, respectively. These numbers are consistent with the AGN fraction in low-redshift clusters, groups and the field. The above results, although affected by small number statistics, suggest that X-ray AGN are spread over a range of environments, from groups to the field, once the properties of their hosts (e.g. colour, luminosity) are accounted for. There is also tentative evidence, significant at the 98 per cent level, that the field produces more X-ray luminous AGN compared to groups, extending similar results at low redshift to z ~ 1. This trend may be because of either cold gas availability or the nature of the interactions occurring in the denser group environment (i.e. prolonged tidal encounters).
Bibtex entry for this abstract   Preferred format for this abstract (see Preferences)
   

Find Similar Abstracts:

Use: Authors
Title
Keywords (in text query field)
Abstract Text
Return: Query Results Return    items starting with number
Query Form
Database: Astronomy
Physics
arXiv e-prints