Comparison between the influence of outflows and supermassive binary
  black holes in active galactic nuclei on the polarization angle profiles
  Optical polarization signal coming from the innermost part of active galactic
nuclei (AGNs) is highly sensitive on the geometry and kinematics of the central
engine. Due to the compact size of the AGN central region, which is spatially
unresolved with current observing facilities, we rely on spectropolarimetry
which can provide us insight in their hidden physics. We model equatorial
scattering for various broad line region (BLR) configurations using radiative
transfer code STOKES. We analyze the polarization position angle () profiles
for four supermassive binary black holes (SMBBHs) models and compare them with
the profiles found for a unified model in AGNs with a single supermassive black
hole (SMBH) and with notable outflowing velocity component of the BLR.. We find
that the profiles for SMBBHs are axis-symmetric, while the profiles for a
single SMBHs are point-symmetric and that there is a clear distinction between
the two cases. Our conclussion is that spectropolarimetry might play a key role
in the search for the SMBBHs by inspecting the polarization angle profiles.
