HIGH-FREQUENCY RADIO-CONTINUUM OBSERVATIONS OF RADIO GALAXIES WITH LOW AND INTERMEDIATE LUMINOSITY .2. SOURCES WITH SIZES 4' TO 5'

We have mapped 17 low and intermediate luminosity radio galaxies with angular sizes between 4' and 5' using the Effelsberg 100-m telescope. These sources were selected from the B2 and 4C catalogue in an on-going project to study the high-frequency radio continuum and polarization characteristics of such sources. The integrated radio spectra between 408 MHz and 10.6 GHz are found to resemble those of strong 3C sources, the average spectral index being alpha=-0.69+/-0.02(S-nu proportional to nu(alpha)). In most of the sources, high degrees of linear polarization are seen, indicating that the magnetic fields in these sources are ordered over large scales. The orientation of the magnetic fields exhibits a clear trend of two preferential direction configurations, viz. parallel and perpendicular to the sources, axes or, equivalently, their jets. Furthermore, the trend for fields to prevail in sources with brighter cores is indicated in our data, despite the small sample of sources involved in this study.