Spectropolarimetric Observations of Active Galactic Nuclei with the 6-m   BTA Telescope
  We present the results of our spectropolarimetric observations for a number of active galactic nuclei (AGNs) carried out at the 6-m telescope with the SCORPIO focal reducer. The derived wavelength dependences of the polarization have been analyzed by taking into account the Faraday rotation of the polarization plane on the photon mean free path in a magnetized accretion disk. As a result, based on traditional accretion disk models, we have determined the magnetic field strength and distribution and a number of physical parameters of the accreting plasma in the region where the optical radiation is generated. 
V.L. Afanasiev, N.V. Borisov, Yu.N. Gnedin, T.M. Natsvlishvili, M.Yu.   Piotrovich and S.D. Buliga
astro-ph.GA astro-ph.CO