AGN environments at z<1.5 in the UKIDSS Ultra-Deep Survey

Authors :: Bradshaw, E. J.
Almaini, O.
Hartley, W. G.
Chuter, R. W.
Simpson, C.
Conselice, C. J.
Dunlop, J. S.
McLure, R. J.
Cirasuolo, M.
Publication Year :: 2011
Publisher :: arXiv, 2011.
Abstract: We investigate the environments of both X-ray and radio-loud AGN within the UKIDSS Ultra-deep Survey (UDS) using deep infrared selection to sample the galaxy density field in the redshift range 1.0 ~ 10^13 M_sun. A closer look at the small-scale environments of the AGN reveals that the neighbouring galaxies of radio-loud AGN have U-B colours more skewed towards the `green-valley' and the red sequence, whereas the neighbours of X-ray AGN show no difference to the general galaxy population. This suggests that although both AGN types live in overdense environments, the radio-loud AGN may be preferentially located in more evolved cluster cores, in a similar environment to low-powered radio AGN in the local Universe.<br />12 pages, 7 figures, Accepted for publication in MNRAS