your ID: 0295 
First Name: Thomas 
Last Name: Beckert 
Affiliation: Max-Planck-Institute for Radioastronomy 

Title: Nuclear dusty tori across the luminosity range 
Authors: T. Beckert, B. Vollmer,  S. Hoenig, G. Weigelt, W.J. Duschl 
Topic: 6 
Session: oral 

Abstract: Based on a model for a clumpy and dusty torus surrounding accreting supermassive
 black holes (Beckert \\& Duschl 2004), we discuss the near to mid-infrared emission of AGN
 and consequences for the required accretion rates. 
Both dynamical arguments and the weakness of spectral features in the infrared suggest that 
dust in the torus is organized in distinct clouds. The optical depth of individual clouds is so
 large that the clumpiness of the torus is important for the shape of the broad-band spectrum 
and the appearance of AGN in high spatial resolution observations (Hoenig et al. 2006). 
The thickness of the torus in the underlying dynamical model depends on the mass accretion 
rate through the torus on parsec-scales. A geometrically thick torus can exist in luminous AGN
 for which the \'unified model\' has been developed. In low luminosity AGN the clumpy
 distribution of clouds becomes transparent and the appearance in the infrared is markedly different.