The Evolution of Radio Galaxies and X-ray Point Sources in Coma Cluster
  Progenitors Since z~1.2
  Using Chandra imaging spectroscopy and Very Large Array (VLA) L-band radio
maps, we have identified radio sources at P_{1.4GHz} >=5x10^{23} W Hz^{-1} and
X-ray point sources (XPSs) at L_{0.3-8keV}>=5x10^{42} erg s^{-1} in L>L*
galaxies in 12 high-redshift (0.4<z<1.2) clusters of galaxies. The radio
galaxies and XPSs in this cluster sample, chosen to be consistent with Coma
Cluster progenitors at these redshifts, are compared to those found at low-z
analyzed in Hart et al. (2009). Within a projected radius of 1 Mpc of the
cluster cores, we find 17 cluster radio galaxies (11 with secure redshifts,
including one luminous FR II radio source at z=0.826, and 6 more with host
galaxy colors similar to cluster ellipticals). The radio luminosity function
(RLF) of the cluster radio galaxies as a fraction of the cluster red sequence
(CRS) galaxies reveals significant evolution of this population from high-z to
low-z, with higher power radio galaxies situated in lower temperature clusters
at earlier epochs. Additionally, there is some evidence that cluster radio
galaxies become more centrally concentrated than CRS galaxies with cosmic time.
Within this same projected radius, we identify 7 spectroscopically-confirmed
cluster XPSs, all with CRS host galaxy colors. Consistent with the results from
Martini et al. (2009), we estimate a minimum X-ray active fraction of
1.4+/-0.8% for CRS galaxies in high-z clusters, corresponding to an approximate
10-fold increase from 0.15+/-0.15% at low-z. Although complete redshift
information is lacking for several XPSs in z>0.4 cluster fields, the increased
numbers and luminosities of the CRS radio galaxies and XPSs suggest a
substantial (9-10 fold) increase in the heat injected into high redshift
clusters by AGN compared to the present epoch.
