Constraining the Redshift Evolution of FIRST Radio Sources in RCS1
  Galaxy Clusters
  We conduct a statistical analysis of the radio source population in galaxy
clusters as a function of redshift by matching radio sources from the Faint
Images of the Radio Sky at Twenty-Centimeters (FIRST) catalog with 618
optically-selected galaxy clusters from the first Red-Sequence Cluster Survey
(RCS1). The number of excess radio sources (above the background level) per
cluster is 0.14 +/- 0.02 for clusters with 0.35 < z < 0.65 and is 0.10 +/- 0.02
for clusters with 0.65 < z < 0.95. The richest clusters in the sample have more
radio sources than clusters with low or intermediate richness. When we divide
our sample into bins according to cluster richness, we do not observe any
significant difference (> 1.5 sigma) in the number of radio sources per unit of
cluster mass for the galaxy clusters with 0.35 < z < 0.65 as compared to the
galaxy clusters with 0.65 < z < 0.95. Thus the entire sample can be
characterized by the number of (L(1.4 GHz) > 4.1 X 10^(24) W/Hz) radio sources
per unit (10^14 solar masses) mass, which we measure to be 0.031 +/- 0.004. We
further characterize the population of galaxy cluster-related radio sources
through visual inspection of the RCS1 images, finding that although the radio
activity of brightest cluster galaxies (BCGs) also does not strongly evolve
between our high and low redshift samples, the lower-redshift, richest clusters
are more likely to host radio-loud BCGs than the higher-redshift, richest
clusters or poorer clusters at the 2-sigma level.
