The local environments of low-redshift quasars and powerful radio galaxies

The local environments of 31 low-redshift QSOs and 35 powerful radio galaxies (PRGs) are studied on the basis of V and R CCD frames processed to generate catalogs of companion galaxies. The PRGs and radio-loud QSOs are noted to inhabit regions whose local galaxy densities are similar to normal giant ellipticals and 3-4 times less dense than the regions inhabited by lower power radio-loud elliptical galaxies. The brightest companion galaxy is on average about 2 mag dimmer than the QSO host galaxy or PRG. Attention is given to the implications of these results for theories of the origin of nuclear activity, as well as the relationship between various classes of active galaxies and QSOs.