X-ray bright AGN in massive galaxy clusters

With a sample of more than 11000 X-ray point sources, we are able to measure, for the first time, evidence for evolution in the cluster AGN population beyond the expected evolution of field AGN. Our analysis shows that overall number density of cluster AGN scales with the cluster mass as ~M_500_-1.2.

There is no evidence for the overall number density of cluster member X-ray AGN depending on the cluster redshift in a manner different than field AGN, nor is there any evidence that the spatial distribution of cluster AGN (given in units of the cluster overdensity radius r_500_) strongly depends on the cluster mass or redshift. The M^-1.2+/-0.7^ scaling relation we measure is consistent with theoretical predictions of the galaxy merger rate in clusters, which is expected to scale with the cluster velocity dispersion, {sigma}, as ~{sigma}^-3^ or ~M^-1^.