Hidden Broad-line Regions in Seyfert 2 Galaxies: from the
  spectropolarimetric perspective
  The hidden broad-line regions (BLRs) in Seyfert 2 galaxies, which display
broad emission lines (BELs) in their polarized spectra, are a key piece of
evidence in support of the unified model for active galactic nuclei (AGNs).
However, the detailed kinematics and geometry of hidden BLRs are still not
fully understood. The virial factor obtained from reverberation mapping of type
1 AGNs may be a useful diagnostic of the nature of hidden BLRs in type 2
objects. In order to understand the hidden BLRs, we compile six type 2 objects
from the literature with polarized BELs and dynamical measurements of black
hole masses. All of them contain pseudobulges. We estimate their virial
factors, and find the average value is 0.60 and the standard deviation is 0.69,
which agree well with the value of type 1 AGNs with pseudobulges. This study
demonstrates that (1) the geometry and kinematics of BLR are similar in type 1
and type 2 AGNs of the same bulge type (pseudobulges), and (2) the small values
of virial factors in Seyfert 2 galaxies suggest that, similar to type 1 AGNs,
BLRs tend to be very thick disks in type 2 objects.
