Active galactic nuclei among polar-ring galaxies
  Based on SDSS data, we consider the fraction of active galactic nuclei among
polar-ring galaxies. We have found evidence for an excess of Seyfert galaxies
and LINERs among polar-ring galaxies compared to ordinary objects. The observed
nuclear activity of polar-ring galaxies may be associated with the accretion of
gas from the region of the polar structures onto the central galaxies.
