The cluster environments of powerful radio-loud and radio-quiet active galactic nuclei

The spatial clustering amplitude (B-gq) is determined for a sample of 44 po werful active galactic nuclei (AGN) at z similar or equal to 0.2. No signif icant difference is detected in the richness of the cluster environments of the radio-loud and radio-quiet subsamples, both of which typically inhabit environments as rich as Abell class similar or equal to0. Comparison with radio luminosity-matched samples from Hill & Lilly and Wold et al. suggests that there is no epoch-dependent change in environment richness out to at least z greater than or equal to 0.5 for either radio galaxies or radio qua sars. Comparison with the APM cluster survey shows that, contrary to curren t folklore, powerful AGN do not avoid rich clusters, but rather display a s pread in cluster environment, which is perfectly consistent with being draw n at random from the massive elliptical population. Finally, we argue that virtually all Abell class similar or equal to0 clusters contained an active galaxy during the epoch of peak quasar activity at z similar to 2.5.