We used the CLUMPY torus models and a Bayesian approach to fit the infrared spectral energy distributions ( SEDs ) and ground-based high-angular resolution mid-infrared spectroscopy of 13 nearby Seyfert galaxies .
This allowed us to put tight constraints on torus model parameters such as the viewing angle i , the radial thickness of the torus Y , the angular size of the cloud distribution \sigma _ { torus } , and the average number of clouds along radial equatorial rays N _ { 0 } .
We found that the viewing angle i is not the only parameter controlling the classification of a galaxy into a type 1 or a type 2 .
In principle type 2s could be viewed at any viewing angle i as long as there is one cloud along the line of sight .
A more relevant quantity for clumpy media is the probability for an AGN photon to escape unabsorbed .
In our sample , type 1s have relatively high escape probabilities , P _ { esc } \sim 12 - 44 \% , while type 2s , as expected , tend to have very low escape probabilities .
Our fits also confirmed that the tori of Seyfert galaxies are compact with torus model radii in the range 1-6 pc .
The scaling of the models to the data also provided the AGN bolometric luminosities L _ { bol } ( { AGN } ) , which were found to be in good agreement with estimates from the literature .
When we combined our sample of Seyfert galaxies with a sample of PG quasars from the literature to span a range of L _ { bol } ( { AGN } ) \sim 10 ^ { 43 } -10 ^ { 47 } { erg s } ^ { -1 } , we found plausible evidence of the receding torus .
That is , there is a tendency for the torus geometrical covering factor to be lower ( f _ { 2 } \sim 0.1 - 0.3 ) at high AGN luminosities than at low AGN luminosities ( f _ { 2 } \sim 0.9 - 1 at \sim 10 ^ { 43 - 44 } { erg s } ^ { -1 } ) .
This is because at low AGN luminosities the tori appear to have wider angular sizes ( larger \sigma _ { torus } ) and more clouds along radial equatorial rays .
We can not , however rule out the possibility that this is due to contamination by extended dust structures not associated with the dusty torus at low AGN luminosities , since most of these in our sample are hosted in highly inclined galaxies .