Investigating the sensitivity of observed spectral energy distributions
  to clumpy torus properties in Seyfert galaxies
  We present nuclear spectral energy distributions (SEDs) from 1 to 18 micron
of a small sample of nearby, nearly face-on and undisturbed Seyfert galaxies
without prominent nuclear dust lanes. These nuclear SEDs probe the central ~35
pc of the galaxies, on average, and include photometric and spectroscopic
infrared (IR) data. We use these SEDs, the clumpy torus models of Nenkova et
al. and a Bayesian approach to study the sensitivity of different IR
wavelengths to the torus parameters. We find that high angular resolution 8-13
micron spectroscopy alone reliably constrains the number of clumps and their
optical depth (N0 and tau_V). On the other hand, we need a combination of mid-
and near-IR subarcsecond resolution photometry to constrain torus width and
inclination, as well as the radial distribution of the clouds (sigma, i and q).
For flat radial profiles (q=0,1), it is possible to constrain the extent of the
mid-IR-emitting dust within the torus (Y) when N-band spectroscopy is
available, in addition to near-IR photometry. Finally, by fitting different
combinations of average and individual Seyfert 1 and Seyfert 2 data, we find
that, in general, for undisturbed, nearly face-on Seyferts without prominent
nuclear dust lanes, the minimum combination of data necessary to reliably
constrain all the torus parameters is J+K+M-band photometry + N-band
spectroscopy.
