A high-frequency radio continuum investigation of giant radio galaxies. II. Observations of four objects at 2.8cm wavelength.

Abstract

We present 10.6GHz radio observations in total intensity and polarization of the four radio galaxies 3C130, 1331-099, 1358+305, and 4C74.26, made with the Effelsberg 100-m telescope. These measurements add to our sample of observations of giant radio galaxies (GRGs) observed at λ2.8cm. The high-frequency lobe characteristics of GRGs are reviewed. It is found that the axial ratios of the GRGs at this wavelength do not differ significantly from those at longer wavelengths, implying a maximum age for the GRGs of ~3x10^7^yrs. The magnetic fields are mostly uniform over the lobes. While in some edge-brightened GRGs the expected circumferential magnetic field is seen at the lobe extremities, this is not the case in others. The magnetic field structures in the lobes of asymmetric GRGs depend more on the individual lobe structures than on the separation of the lobes from the cores. However, a higher percentage polarization is seen in the more distant lobes in 5 out of 7 asymmetric GRGs.