Estimation of the size and structure of the broad line region using
  Bayesian approach
  Understanding the geometry and kinematics of the broad line region (BLR) of
active galactic nuclei (AGN) is important to estimate black hole masses in AGN
and study the accretion process. The technique of reverberation mapping (RM)
has provided estimates of BLR size for more than 100 AGN now, however, the
structure of the BLR has been studied for only a handful number of objects.
Towards this, we investigated the geometry of the BLR for a large sample of 57
AGN using archival RM data. We performed systematic modeling of the continuum
and emission line light curves using a Markov Chain Monte Carlo method based on
Bayesian statistics implemented in PBMAP (Parallel Bayesian code for
reverberation-MAPping data) code to constrain BLR geometrical parameters and
recover velocity integrated transfer function. We found that the recovered
transfer functions have various shapes such as single-peaked, double-peaked and
top-hat suggesting that AGN have very different BLR geometries. Our model lags
are in general consistent with that estimated using the conventional
cross-correlation methods. The BLR sizes obtained from our modeling approach is
related to the luminosity with a slope of 0.583 (+/-) 0.026 and 0.471 (+/-)
0.084 based on H{\beta} and H{\alpha} lines, respectively. We found a
non-linear response of emission line fluxes to the ionizing optical continuum
for 93\% objects. The estimated virial factors for the AGN studied in this work
range from 0.79 to 4.94 having a mean at 1.78 (+/-) 1.77 consistent with the
values found in the literature.
