An optical and near-infrared polarization survey of Seyfert and broad-line radio galaxies. 1 : statistical properties

The present broad-band and near-IR flux density and polarization measurements of a sample of 71 Seyfert galaxies and three broad-line radio galaxies confirms earlier indications that the polarization of Seyferts is generally low in the V-band and at longer wavelengths. A tendency is noted for the polarization to be parallel to the galaxy optical or dust-lane axis; previous indications that the polarization of Seyfert 2s tends to be perpendicular to the radio axis are confirmed. In the second part of this work, the 0.44-2.2 micron wavelength dependence of polarization for this sample of 71 Seyfert and three broad-line radio galaxies is discussed. Most objects in the sample exhibit decreasing polarization with increasing wavelength, as may be expected in polarization induced by either dichroic absorption or scattering.