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Abstract: We present the surface density of luminous active galactic nuclei AGNassociated with a uniformly selected galaxy cluster sample identified in the8.5 square degree Bootes field of the NOAO Deep Wide-Field Survey. The clustersare distributed over a large range of redshift 0 < z < 1.5 and we identifyAGN using three different selection criteria: mid-IR color, radio luminosity,and X-ray luminosity. Relative to the field, we note a clear overdensity of thenumber of AGN within 0.5 Mpc of the cluster centers at z > 0.5. The amplitudeof this AGN overdensity increases with redshift. Although there are significantdifferences between the AGN populations probed by each selection technique, therise in cluster AGN surface density generally increases more steeply than thatof field quasars. In particular, X-ray selected AGN are at least three timesmore prevalent in clusters at 1 < z < 1.5 compared to clusters at 0.5 < z < 1.This effect is stronger than can be explained by the evolving median richnessof our cluster sample. We thus confirm the existence of a Butcher-Oemler typeeffect for AGN in galaxy clusters, with the number of AGN in clustersincreasing with redshift.



Author: Audrey Galametz, Daniel Stern, Peter R. M. Eisenhardt, Mark Brodwin, Michael J. I. Brown, Arjun Dey, Anthony H. Gonzalez, Buell T

Source: https://arxiv.org/







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