X-ray Point Sources and Radio Galaxies in Clusters: Source of
  Distributed Heating of the ICM?
  In our ongoing multi-wavelength study of cluster AGN, we find ~75% of the
spectroscopically identified cluster X-ray point sources (XPS) with
L(0.3-8.0keV)>10^{42} erg s^{-1} and cluster radio galaxies with P(1.4 GHz) >
3x10^{23} W Hz^{-1} in 11 moderate redshift clusters (0.2<z<0.4) are located
within 500 kpc from the cluster center. In addition, these sources are much
more centrally concentrated than luminous cluster red sequence (CRS) galaxies.
With the exception of one luminous X-ray source, we find that cluster XPSs are
hosted by passive red sequence galaxies, have X-ray colors consistent with an
AGN power-law spectrum, and have little intrinsic obscuring columns in the
X-ray (in agreement with previous studies). Our cluster radio sources have
properties similar to FR1s, but are not detected in X-ray probably because
their predicted X-ray emission falls below our sensitivity limits. Based on the
observational properties of our XPS population, we suggest that the cluster
XPSs are low-luminosity BL Lac objects, and thus are beamed low-power FR 1s.
Extrapolating the X-ray luminosity function of BL Lacs and the Radio luminosity
function of FR 1s down to fainter radio and X-ray limits, we estimate that a
large fraction, perhaps all CRSs with L>L* possess relativistic jets which can
inject energy into the ICM, potentially solving the uniform heating problem in
the central region of clusters.
