The Lunar Occultation Of The Crab Nebula Observed At Parkes On June 21, 1963

Abstract

Measurements of the intensity and percentage linear polarization of the Crab nebula radiation at 404 and 1420 Mc/s were made during the partial occultation of .June 21, 1963. The radio occultation curves are similar in shape to that calculated from the isophotes of the optical continuum and show the same principal features. However, the ratio of radio to optical brightness varies in a systematic way across the source, the ratio being greater at the edges than in the central regions. This steepening of the spectral index towards the outer edges continues in the radio frequency range from 1420 to 404 Mc/s. The 1420 Mc/s linear polarization is stronger in the inner areas (2,5%) than in the outer areas (< 1%) of the source.