Preliminary measurements on the distribution of linear polarization over eight radio sources

Abstract

The feasibility of the determination of polarization distributions over radio sources by varialt spacing interference polarimetry has been tested. The results of preliminary measurements for eig strong sources are presented. The polarized region in the Crab Nebula at 10.6-cm wavelength is rough one-half the diameter of the unpolarized source. Both components of the central source in Centaurus are found to be linearly polarized, but with their planes of polarization at 44° to each other. The observ tions on five other double sources, 3C 270, Pictor A, Hercules A, 3C 353 and Cygnus A show evidence two or more polarized regions on each source with different preferred directions. M87, the galaxy wi the optically polarized "jet," seems to have a polarized halo at 21 cm, whereas earlier measuremen at the same wavelength had indicated that the core was essentially unpolarized.