Polarization of Radio Sources. I. Homogeneous Source of Arbitrary Optical Thickness

Solutions of the equation of transfer are obtained, and the degree of polarization is derived for a homogeneous source in which polarized emission, polarized absorption, and Faraday rotation aie included. Only 6ptically thin cases have been considered in previous works, and the present equations show how the polarization is influenced by absorption Polarization measurements may help to determine whether synchrotron self-absorption, thermal absorption, or another process is responsible for the curvature in the spectra of certain radio sources at the low frequencies in which absorption is thought to be important.