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arXiv · 1310.5711

X-ray Bright Active Galactic Nuclei in Massive Galaxy Clusters II: The Fraction of Galaxies Hosting Active Nuclei

S. Ehlert·A. von der Linden·S. W. Allen·W. N. Brandt·Y. Q. Xue·B. Luo·A. Mantz·R. G. Morris·D. Applegate·P. Kelly
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Abstract

We present a measurement of the fraction of cluster galaxies hosting X-ray bright Active Galactic Nuclei (AGN) as a function of clustercentric distance scaled in units of $r_{500}$. Our analysis employs high quality Chandra X-ray and Subaru optical imaging for 42 massive X-ray selected galaxy cluster fields spanning the redshift range of $0.2 < z < 0.7$. In total, our study involves 176 AGN with bright ($R <23$) optical counterparts above a $0.5-8.0$ keV flux limit of $10^{-14} \rm{erg} \ \rm{cm}^{-2} \ \rm{s}^{-1}$. When excluding central dominant galaxies from the calculation, we measure a cluster-galaxy AGN fraction in the central regions of the clusters that is $\sim 3 $ times lower that the field value. This fraction increases with clustercentric distance before becoming consistent with the field at $\sim 2.5 r_{500}$. Our data exhibit similar radial trends to those observed for star formation and optically selected AGN in cluster member galaxies, both of which are also suppressed near cluster centers to a comparable extent. These results strongly support the idea that X-ray AGN activity and strong star formation are linked through their common dependence on available reservoirs of cold gas.

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S. Ehlert, A. von der Linden, S. W. Allen, W. N. Brandt, Y. Q. Xue, B. Luo, A. Mantz, R. G. Morris, D. Applegate, P. Kelly. 2013-10-21. X-ray Bright Active Galactic Nuclei in Massive Galaxy Clusters II: The Fraction of Galaxies Hosting Active Nuclei. https://doi.org/10.1093/mnras%2Fstt2025

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