1420 MHz Continuum and Polarization Observations of the Cygnus Loop

High resolution 1420 MHz total intensity and polarization maps of the Cygnus Loop are presented. The observations were made with the new polarimetry instrumentation at the Dominion Radio Astrophysical Observatory Synthesis Telescope. The Cygnus Loop shows up to 39% polarization in southern regions, and up to 32% in the northern regions. However, the bright northeastern rim has a mean of only 2.4% polarization. Comparison with x-ray images shows a probable correlation between regions bright in x-rays (i.e., high electron density) and depolarization. The S GHz polarization data of Kundu & Becker (1972, AJ, 77, 459) for the southern regions of the Cygnus Loop were used with the 1420 MHz data to derive rotation measures and intrinsic polarization vectors. The bright filaments are found to have the magnetic field aligned along their long dimension.