HIGH-ENERGY GAMMA-RADIATION FROM EXTRAGALACTIC RADIO-SOURCES

We propose that the important relationship between 3C 273 and 3C 279, the first two extragalactic sources detected at > 100 MeV energies, is their superluminal nature. In support of this conjecture, we propose a kinematic focusing mechanism, based on Compton scattering of accretion-disk photons by relativistic nonthermal electrons in the jet, that preferentially emits gamma rays in the superluminal direction.