Measurements of Flux Density and Polarization of Variable Sources at a Wavelength of 1.55 Centimeters

The flux density of the 1.55-cm radiation from the quasi-stellar sources 3C 273, 3C 279, and 3C 454.3 and the Seyfert galaxy 3C 84 has been observed at intervals of about 2 months from 1966 May to 1968 May; measurements of linear polarization were made during the last half of this interval. Time variations of about 30 percent were found in the fluxes of these sources. In the case of 3C 273, two distinct maxima have been observed, and there is some evidence that the cloud of relativistic electrons which produced the later peak originated at an earlier epoch than the cloud which caused the first observed peak. The measurements of linear polarization indicate a systematic variation in the polarization of 3C 454.3. I. INTRODUCTIO