Obscuring Material around Seyfert Nuclei with Starbursts

The structure of obscuring matter in the environment of active galacticnuclei with associated nuclear starbursts is investigated using 3-Dhydrodynamical simulations. Simple analytical estimates suggest that theobscuring matter with energy feedback from supernovae has a torus-likestructure with a radius of several tens of parsecs and a scale height of about10 pc. These estimates are confirmed by the fully non-linear numericalsimulations, in which the multi-phase inhomogeneous interstellar matter and itsinteraction with the supernovae are consistently followed. The globally stable,torus-like structure is highly inhomogeneous and turbulent. To achieve the highcolumn densities (> 10^{24} cm^{-2}) as suggested by observations of someSeyfert 2 galaxies with nuclear starbursts, the viewing angle should be largerthan about 70 degree from the pole-on for a 10^8 solar mass massive black hole.Due to the inhomogeneous internal structure of the torus, the observed columndensity is sensitive to the line-of-sight, and it fluctuates by a factor oforder 100. The covering fraction for N > 10^{23} cm^{-2} is about 0.4. Theaverage accretion rate toward R < 1 pc is 0.4 solar mass/yr, which is boostedto twice that in the model without the energy feedback.