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 \pm 0.02 for clusters with 0.35 < z < 0.65 and is 0.10 \pm 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 \times 10 ^ { 24 } W Hz ^ { -1 } ) radio sources per unit ( 10 ^ { 14 } M _ { \odot } ) mass , which we measure to be 0.031 \pm 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 .