New mechanism of radiation polarization in Seyfert-1 AGNs
  In most of Seyfert-1 active galactic nucei (AGN) the optical linear continuum
polarization degree is usually small (less than 1%) and the polarization
position angle is nearly parallel to the AGN radio-axis. However, there are
many types-1 AGNs with unexplained intermediate values for both positional
angles and polarization degrees. Our explanation of polarization degree and
positional angle of Seyfert-1 AGNs focuses on the reflection of non-polarized
radiation from sub-parsec jets in optically thick accretion discs. The presence
of a magnetic field surrounding the scattering media will induce Faraday
rotation of the polarization plane that may explain the intermediate values of
positional angles if there is a magnetic field component normal to the
accretion disc. The Faraday rotation depolarization effect in disc diminishes
the competition between polarization of the reflected radiation with the
parallel component of polarization and the perpendicular polarization from
internal radiation of disc (the Milne problem) in favor of polarization of
reflected radiation. This effect allows us to explain the observed polarization
of Seyfert-1 AGN radiation even though the jet optical luminosity is much lower
than the luminosity of disc. We present the calculation of polarization degrees
for a number of Seyfert-1 AGNs.
