Spectra and linear polarizations of extragalactic variable sources at centimeter wavelengths

The results of multifrequency observations of the flux densities and linear polarizations of 97 extragalactic sources obtained with the University of Michigan 26 m paraboloid through November 1984 are presented. The observations were started at 8.0 GHz in June 1965, at 14.5 GHz in February 1974, and at 4.8 GHz in September 1977. The data show that the degrees of polarization of these objects at centimeter wavelengths rarely exceed 15 percent and are typically on the order of 5 percent or less. In many, but not all, sources the observed variations are significantly faster and have a larger amplitude at the highest frequency. The majority of the sources appear to have preferred orientations of the electric vector of the polarized emission which exist over successive outbursts in total flux density.