X-ray Point Sources and Radio Galaxies in Clusters of Galaxies
  Using Chandra imaging spectroscopy and VLA L-band maps, we have identified
radio galaxies at P(1.4 GHz) >= 3x10^{23} W Hz^{-1} and X-ray point sources
(XPSs) at L(0.3-8 keV) >= 10^{42} ergs s^{-1} in 11 moderate redshift
(0.2<z<0.4) clusters of galaxies. Each cluster is uniquely chosen to have a
total mass similar to predicted progenitors of the present-day Coma Cluster.
Within a projected radius of 1 Mpc we detect 20 radio galaxies and 8 XPSs
confirmed to be cluster members above these limits. 75% of these are detected
within 500 kpc of the cluster center. This result is inconsistent with a random
selection from bright, red sequence ellipticals at the > 99.999% level. All but
one of the XPSs are hosted by luminous ellipticals which otherwise show no
other evidence for AGN activity. These objects are unlikely to be highly
obscured AGN since there is no evidence for large amounts of X-ray or optical
absorption. The most viable model for these sources are low luminosity BL Lac
Objects. The expected numbers of lower luminosity FR 1 radio galaxies and BL
Lacs in our sample converge to suggest that very deep radio and X-ray images of
rich clusters will detect AGN in a large fraction of bright elliptical galaxies
in the inner 500 kpc. Because both the radio galaxies and the XPSs possess
relativistic jets, they can inject heat into the ICM. Using the most recent
scalings of P_jet ~ L_radio^{0.5} from Birzan et al. (2008), radio sources
weaker than our luminosity limit probably contribute the majority of the heat
to the ICM. If a majority of ICM heating is due to large numbers of low power
radio sources, triggered into activity by the increasing ICM density as they
move inward, this may be the feedback mechanism necessary to stabilize cooling
in cluster cores.
