1995A&A...297L..13V

We compare the Phase 1 gamma-ray detections and nondetections of active galactic nuclei by the EGRET instrument of Compton Gamma Ray Observatory with Metsaehovi 22GHz and 37Ghz radio flux curves. We find a good correlation betweenthe type of the source, the radio state of the source, and the gamma-ray emission. With few exceptions, gamma-rays are detected when, and only when, a quasar with high optical polarization is in the initial phases of a high radio frequency outburst. Other types of sources - low polarization quasars, BL Lac objects, radio galaxies - are rarely detected in gamma-rays, even when in a similar state of radio activity. Our results limit viable gamma-ray production mechanisms to those involving strongly beamed gamma-rays from radio-emitting shocks in jets oriented close to our line of sight.