Large-scale polarimetry of large optical galaxies

We present preliminary results of wide-field visual CCD polarimetry for lar ge optical galaxies through a concentric multisector radial-tangential pola roid analyzer mounted at the intermediate focus of a Zeiss-1000 telescope. The mean degree of tangential polarization in a 13' field, which was determ ined by processing images with imprinted "orthogonal" sectors, ranges from several percent (M 82) and 0.5-1% (the spirals M 51, M 81) to lower values for elliptical galaxies (M 49, M 87). It is emphasized that the parameters of large-scale polarization can be properly determined by using physical mo dels for galaxies; inclination and azimuthal dependences of the degree of p olarization are given for spirals.