The Near‐ and Mid‐Infrared Continuum Emission of Seyfert Nuclei: Constraints on the Models of Obscuring Tori

For an extended sample of Seyfert galaxies we compile from the literature theinfrared fluxes in the four IRAS bands, the ground-based small-beam (~ 5-10")fluxes in the standard Q, N, M, L (or L') bands, and the nuclear (non-stellar)estimated fluxes in the JHK bands. We estimate nuclear fluxes in the L band byapplying a correction for stellar light. From the statistical study of theinfrared colors and luminosities, we derive the typical SEDs of Seyfert 1 and 2nuclei and the typical differences in luminosities between the two types ofobjects in the mid- and near-infrared spectral ranges. The observational data appear to severely challenge many models of dustytori, which hardly account for the shapes of the SEDs and the degree ofanisotropy observed in Seyfert galaxies. In particular, at variance with someearlier claims, very thick and compact tori are basically inconsistent withthese observational constraints. The most successful models, though havingproblems in accounting for several details, can fit the major infraredobservational data of both Seyfert 1 and Seyfert 2 nuclei with tori whichextend up to several hundreds pc and have fairly low optical thickness.Comment: 18 pages, LaTeX2e, accepted by The Astrophysical Journa