Geometrically thick obscuration by radiation-driven outflow from
  magnetized tori of active galactic nuclei
  Near-Eddington radiation from active galactic nuclei (AGNs) has significant
dynamical influence on the surrounding dusty gas, plausibly furnishing AGNs
with geometrically thick obscuration. We investigate this paradigm with
radiative magnetohydrodynamics simulations. The simulations solve the
magnetohydrodynamics equations simultaneously with the infrared (IR) and
ultraviolet (UV) radiative transfer (RT) equations; no approximate closure is
used for RT. We find that our torus, when given a suitable sub-Keplerian
angular momentum profile, spontaneously evolves toward a state in which its
opening angle, density distribution, and flow pattern change only slowly. This
"steady" state lasts for as long as there is gas resupply toward the inner
edge. The torus is best described as a mid-plane inflow and a high-latitude
outflow. The outflow is launched from the torus inner edge by UV radiation and
expands in solid angle as it ascends; IR radiation continues to drive the
wide-angle outflow outside the central hole. The dusty outflow obscures the
central source in soft X-rays, the IR, and the UV over three quarters of solid
angle, and each decade in column density covers roughly equal solid angle
around the central source; these obscuration properties are similar to what
observations imply.
