• Corpus ID: 16710163

All-wavelength Extended Groth strip International Survey: the environment of X-ray sources at z~1

@article{Georgakakis2006AllwavelengthEG,
  title={All-wavelength Extended Groth strip International Survey: the environment of X-ray sources at z~1},
  author={Antonis Georgakakis and Kirpal Nandra and Elise S. Laird and Michael C. Cooper and Brian F. Gerke and Jeffrey A. Newman and Darren J. Croton and Marc Davis and S. M. Faber and Alison L. Coil},
  journal={arXiv: Astrophysics},
  year={2006}
}

• A. Georgakakis, K. Nandra, +7 authors A. Coil
• Published 12 July 2006
• Physics
• arXiv: Astrophysics

Author(s): Georgakakis, A; Nandra, K; Laird, ES; Cooper, MC; Gerke, BF; Newman, JA; Croton, DJ; Davis, M; Faber, SM; Coil, AL | Abstract: We explore the environment of z~1 AGN using a sample of 53 spectroscopically identified X-ray sources in the All-wavelength Extended Groth strip International Survey. We quantify the local density in the vicinity of an X-ray source by measuring the projected surface density of spectroscopically identified optical galaxies within a radius defined by the 3rd nearest neighbour. Our main result is that X-ray selected AGN at z~1 avoid underdense regions at the 99.89% confidence level. Moreover, although we find that the overall population shares the same (rich) environment with optical galaxies of similar U-B and M_B, there is also tentative evidence (96%) that AGN with blue colors (U-Bl1) reside in denser environments compared to optical galaxies. We argue that the results above are a consequence of the whereabouts of massive galaxies, capable of hosting supermassive black holes at their centers, with available cold gas reservoirs, the fuel for AGN activity. At z~1 an increasing fraction of such systems are found in dense regions.