Obscuring material around Seyfert nuclei with starbursts

The structure of obscuring matter in the environment of active galactic nuclei with associated nuclear starbursts is investigated using three-dimensional hydrodynamical simulations. Simple analytical estimates suggest that the obscuring matter with energy feedback from supernovae has a torus-like structure with a radius of several tens of parsecs and a scale height of 10 pc. These estimates are confirmed by the fully nonlinear numerical simulations, in which the multiphase inhomogeneous interstellar matter and its interaction with the supernovae are consistently followed. The globally stable, torus-like structure is highly inhomogeneous and turbulent. To achieve the high column densities (greater than or similar to10(24) cm(-2)) as suggested by observations of some Seyfert 2 galaxies with nuclear starbursts, the viewing angle should be larger than about 70degrees from the pole-on for a 10(8) M. massive black hole. Owing to the inhomogeneous internal structure of the torus, the observed column density is sensitive to the line of sight, and it fluctuates by a factor on the order of similar to100. The covering fraction for N > 10(23) cm(-2) is about 0.4. The average accretion rate toward R < 1 pc is ∼0.4 M. yr(-1), which is boosted to twice that in the model without the energy feedback.