The Infrared Nuclear Emission of Seyfert Galaxies on Parsec Scales:
  Testing the Clumpy Torus models
  We present subarcsecond resolution mid-infrared (mid-IR) photometry in the
wavelength range from 8 to 20 micron of eighteen Seyfert galaxies, reporting
high spatial resolution nuclear fluxes for the entire sample. We construct
spectral energy distributions (SEDs) that the AGN dominates adding near-IR
measurements from the literature at similar angular resolution. The IR SEDs of
intermediate-type Seyferts are flatter and present higher 10 to 18 micron
ratios than those of Seyfert 2. We fit the individual SEDs with clumpy torus
models using the in-house-developed BayesClumpy tool. The models reproduce the
high spatial resolution measurements. Regardless of the Seyfert type, even with
high spatial resolution data, near- to mid-IR SED fitting poorly constrains the
radial extent of the torus. For the Seyfert 2, we find that edge-on geometries
are more probable than face-on views, with a number of clouds along equatorial
rays of N = 5-15. The 10 micron silicate feature is generally modeled in
shallow absorption. For the intermediate-type Seyferts, N and the inclination
angle of the torus are lower than those of the Seyfert 2 nuclei, with the
silicate feature appearing in weak emission or absent. The columns of material
responsible for the X-ray absorption are larger than those inferred from the
model fits for most of the galaxies, which is consistent with X-ray absorbing
gas being located within the dust sublimation radius whereas the mid-IR flux
arises from an area farther from the accretion disc. The fits yield both the
bolometric luminosity of the intrinsic AGN and the torus integrated luminosity,
from which we derive the reprocessing efficiency of the torus. In the models,
the outer radial extent of the torus scales with the AGN luminosity, and we
find the tori to be confined to scales less than 5 pc.
