VLA observations of radio galaxies with extended lobe emission : 3C 79 and 3C 430.

Dual-frequency (1.446 and 4.885 GHz) total intensity and polarimetric observations have been made with the VLA of the radio galaxies 3C 79 and 3C 430. These sources are characterized by extended lobe and/or radio bridge emission. The 3C 430 galaxy possesses an asymmetric structure which may indicate large-scale inhomogeneities in a confining medium. This source also displays Faraday rotation fluctuations which are apparently unrelated to depolarization, suggesting an origin in an external medium. The present polarization observations suggest that the magnetic fields in both sources possess large-amplitude, random components. In the case of 3C 79, a correlation is observed between depolarization and position-angle rotation. It is unclear whether this is due to internal Faraday rotation, indicating the presence of a large-scale magnetic field, or a Faraday-rotating screen external to the radio-emitting material.