The Kinematics of Quasar Broad Emission Line Regions Using a Disk-wind
  Model
  The structure and kinematics of the broad line region (BLR) in quasars are
still not well established. One popular BLR model is the disk-wind model that
offers a geometric unification of a quasar based on the angle of viewing. We
construct a simple kinematical disk-wind model with a narrow outflowing wind
angle. The model is combined with radiative transfer in the Sobolev, or high
velocity, limit. We examine how angle of viewing affects the observed
characteristics of the emission line, especially the line widths and velocity
offsets. The line profiles exhibit distinct properties depending on the
orientation, wind opening angle, and region of the wind where the emission
arises.
  At low inclination angle (close to face-on), we find the shape of the
emission line is asymmetric with narrow width and significantly blueshifted. As
the inclination angle increases (close to edge-on), the line profile becomes
more symmetric, broader, and less blueshifted. Additionally, lines that arise
close to the base of the disk wind, near the accretion disk, tend to be broad
and symmetric. The relative increase in blueshift of the emission line with
increasing wind vertical distance is larger for polar winds compared with
equatorial winds. By considering the optical thickness of the wind,
single-peaked line profiles are recovered for the intermediate and equatorial
outflowing wind. The model is able to reproduce a faster response in either the
red and blue sides of the line profile found in reverberation mapping studies.
A quicker response in the red side is achieved in the model with a polar wind
and intermediate wind opening angle at low viewing angle. The blue side
response is faster for an equatorial wind seen at high inclination.
