A far-infrared study of the CfA Seyfert sample.: I.: The data

We present mid- and far-IR Infrared Space Observatory data of the CfA Seyfert galaxy sample. These data allow a detailed study of the far-IR spectral energy distribution (SED) of these galaxies. A Bayesian inversion method has been used to invert the SED of these objects and to identify three characteristic temperature ranges of dust emission. The method yields two fundamental results, namely, (1) that the mid- and far-IR SED of Seyfert galaxies can be explained solely through thermal reradiation of higher energy photons by dust; and (2) that this thermal emission is made up of three different components, a warm, a cold, and a very cold dust component. These components are characterized by a peak temperature and their emission dominated in each case by a single astrophysical mechanism. These mechanisms have been readily explained as produced, respectively, by warm dust heated by either the active nucleus or circumnuclear starbursts, cold dust heated by a star-forming region in the galaxy disk, and very cold dust heated by the general interstellar radiation field. Comparisons between the parameters obtained from the analysis of the IR SEDs (fluxes, temperatures, luminosities) have been made. Our results suggest that the emission in the mid-IR is anisotropic and the differences found between Seyfert 1 and Seyfert 2 galaxies could be explained with thin molecular tori models.