Parkes radio sources in the directions of southern rich clusters

Abstract

We have compiled a listing of all Parkes radio sources coincident within 0.3 cluster radii of southern rich clusters of galaxies [Abell et al. ApJS, 70, 1 (1989)]. A pronounced peak of radio sources very near the cluster centers was found. Bautz Morgan type I clusters tend to have more powerful radio sources and are radio loud ≈ 5 times more often than clusters without dominant central galaxies. There is no strong correlation between radio emission and richness class. We find that the slope of the cluster-radio source two-point angular correlation function is twice that of the galaxy-galaxy correlation function. Furthermore, the correlation amplitude for stronger sources (> 0.65 Jy) is nearly twice that of the entire Parkes catalog sample suggesting a tighter correlation with cluster centers for the stronger sources. Finally, the distribution of spectral indices for Parkes sources within ACO clusters is different from that outside the clusters; stronger cluster sources have steeper spectra on average.