Extragalactic radio sources and X-ray astronomy

Methods of extragalactic radio source study in which radio and X-ray observations provide complementary information about physical conditions in active systems are discussed. Some of the effects cited are new, and are the result of high-resolution observations made with the Einstein X-ray Observatory. Attention is drawn to the utility of the radio source's environment, not only in the case of cluster sources, but also those cases in which the cluster of galaxies is significantly weaker. It is also shown that the most extended sources are candidates for scattering of the microwave background radiation, although compact central sources with high IR and optical photon densities are also strong candidates, and that the detailed study of X-ray jets and their relation to their radio and optical counterparts should be considered.