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