Observations of the OWENS VALLEY RADIO OBSERVATORY PRELIMINARY MEASUREMENTS ON THE DISTRIBUTION OF LINEAR POLARIZATION OVER EIGHT RADIO SOURCES

摘要

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