Jet/Environment Interactions of FRI and FRII Radio Galaxies.

We present the results of new XMM-Newton observations of FRI and FRII radio galaxies that show the importance of jet/environment interactions for both radiosource structure and the properties of the surrounding gas. The FRI observations reveal that the distribution of hot gas determines the radio-lobe morphology, and provide evidence that the subsonic expansion of the lobes heats the surrounding gas. The FRII observations show that the sources are at equipartition and in pressure balance with their surroundings. Finally, we present an analysis of a sample of elliptical-dominated groups, showing that radio-source heating is common.