Spectropolarimetry of Seyfert 1 galaxies with equatorial scattering:
  Black hole masses and Broad Line Region characteristics
  Here we present the spectropolarimetric observations of a sample of 30 Type 1
AGNs and an analysis of the observed polarization in these AGNs. The
observations have been performed with the 6-meter telescope of SAO RAS using
the modified SCORPIO-2 spectropolarimeter. We measured the Stokes parameters
for the continuum and the broad H$\alpha$ line and obtained the values of
polarization degree and the angle of polarization. We found that equatorial
scattering is dominant polarization mechanism in the sample, that allows us to
use the observed polarization in the broad lines for determination of the
central black hole (BH) masses and characteristics (the inclination and
emissivity) of the Broad Line Region (BLR). We demonstrated that the recently
proposed method of \cite{ap15} for BH mass measurement gives accurate BH masses
which are in a good correlation with the stellar velocity dispersion, and
consequently the masses determined by the polarization method can be used with
calibration purposes. Additionally we found that the BLR in the sample of 30
AGN has an averaged inclination of $35^\circ\pm9^\circ$ (mostly between 20 and
40 degrees) and emissivity $\alpha\sim -0.57$ that is more flat than one
expected for the classical accretion disc $\alpha\sim -0.75$.
