The intermediate-power population of radio galaxies: morphologies and interactions

Radio galaxies of intermediate power dominate the radio-power injection in the Universe as a whole, due to the break in the radio luminosity function, and so are of special interest. The population spans FR I, FR II, and hybrid morphologies, resides in a full range of environmental richness, and sources of all ages are amenable to study. We describe structures and interactions, with emphasis on sources with deep high-resolution Chandra X-ray data. As compared with low-power sources there is evidence that the physics changes, and the work done in driving shocks can exceed that in evacuating cavities. A range of morphologies and phenomena is identified.