A study of the long-term variability in radio emission of active galaxies

A long-term study of 13 active galaxies has been carried out at 10.7 GHz over the period September 1980 to April 1982. The sources were observed at approximately monthly intervals and most of them were selected because they are also X-ray sources. The data obtained are used to measure their respective variabilities and to search for any correlations with other source parameters. No obvious relationship to radio or X-ray luminosity was found, though there does appear to be two distinct levels of radio variability for these sources and clear evidence of higher X-ray than radio variability.