AGN Dusty Tori. II. Observational Implications of Clumpiness

Clumpy torus models with N0 ~ 5–15 dusty clouds along radial equatorial rays successfully explain AGN infrared observations. The dust has standard Galactic composition, with individual cloud optical depth τV ~ 30–100 at visual. The models naturally explain the observed behavior of the 10 μm silicate feature, in particular the lack of deep absorption features in AGNs of any type, and can reproduce the weak emission feature tentatively detected in type 2 QSOs. The clouds' angular distribution must have a soft edge, e.g., Gaussian, and the radial distribution should decrease as 1/r or 1/r2. In line with recent interferometry, the ratio of the torus outer to inner radius can be as small as ~5-10. The models can…