On the dynamics of clouds in the broad-line region of AGNs with an ADAF
  atmosphere
  We investigate orbital motion of spherical, pressure-confined clouds in the
broad-line region (BLR) of active galactic nuclei (AGN). The combined influence
of gravity of the central object and the non-isotropic radiation of the central
source are taking into account. While most of the previous studies assume that
the pressure of the intercloud gaseous component is proportional to a power-law
function of the radial coordinate, we generalize it to a case where the
external pressure depends on both the radial distance and the latitudinal
angle. Our prescribed pressure profile determines the radius and the column
density of BLR clouds as a function of their location. We also discuss about
stability of the orbits and a condition for the existence of bound orbits is
obtained. We found that BLR clouds tend to populate the equatorial regions more
than other parts simply because of the stability considerations. Although this
finding is obtained for a particular pressure profile, we think, this result is
valid as long as the pressure distribution of the intercloud medium decreases
from the equator to the pole.
