Distribution of Brightness and Polarization in Cassiopeia A at 5.0 GHz

Cas A (3C 461) has been observed at a frequency of 5.0 GHz with a resolving power of $${6}^{\prime\prime{}}.5\,\times\,{7}^{\prime\prime{}}.6\,\text{arc}$$. Further resolution of the fine structure is revealed in the distribution of total intensity, and a study of the variations of structure with frequency is presented. Linear polarization of about 5 per cent has been found around the rim of the source, consistent with a radial component of magnetic field. The distribution of total emission from the source is shown to be consistent with this configuration of magnetic field.