The role of infrared radiation pressure in shaping dusty winds in AGN
  The detection of dusty winds dominating the infrared emission of AGN on
parsec scales has revealed the limitations of traditional radiative transfer
models based on a toroidal distribution of dusty gas. A new, more complex,
dynamical structure is emerging and the physical origin of such dusty winds has
to be critically assessed. We present a semi-analytical model to test the
hypothesis of radiatively accelerated dusty winds launched by the AGN and by
the heated dust itself. The model consists of an AGN and an infrared radiating
dusty disk, the latter being the primary mass reservoir for the outflow. We
calculate the trajectories of dusty gas clumps in this environment, accounting
for both gravity and the AGN radiation as well as the re-radiation by the hot
dusty gas clouds themselves. We find that the morphology consists of a disk of
material that orbits with sub-Keplerian velocities and a hyperboloid polar wind
launched at the inner edge of the dusty disk. This is consistent with
high-angular resolution infrared and sub-mm observations of some local Seyfert
AGN. The strength of the wind and its orientation depend on the Eddington ratio
and the column density of the dusty clumps, which is in agreement with proposed
radiation regulated obscuration models developed for the X-ray obscuring
material around AGN.
