Radio galaxy host properties spanning three dex in radio luminosity

Abstract

We describe a major study of radio source host galaxies being carried out with the HST and ground-based facilities. Our sample is selected from 4 complete samples with different radio flux-density limits, giving a range of three orders of magnitude in radio luminosity at a fixed epoch ( z=0.5). High-resolution HST WFPC2 imaging shows that all 44 radio galaxies have flux distributions well fit by an r^1/4 law and lying on the Kormendy relation defined by lower redshift ellipticals with a shift in the zero-point to account for passive evolution. Spectroscopic follow-up enables stellar velocity dispersions to be determined and black hole masses estimated. The clustering environments of the radio galaxies are being probed via multi-colour wide-field imaging. Together, these data allow a detailed investigation of how factors such as clustering environment, close interactions and star-formation history affect the accretion rate, ionizing luminosity and jet production from supermassive black holes.