THE 10 MICRON EMISSION OF SEYFERT NUCLEI

We examine the 10 mu m emission of the central regions of 117 Seyfert galaxies, after having compiled all the ground-based, small aperture ( similar to 5'') photometric observations at lambda similar to 10 mu m (N-magnitudes) published in the literature. We also evaluate the compa ctness of the 10 mu m emission through a comparison of these small-bea m measures with the large beam IRAS 12 mu m fluxes. We apply survival analysis statistical techniques in order to exploit the information co ntained in ''censored'' data (i.e., upper limits on fluxes). Seyfert g alaxies appear to have more compact and powerful central 10 mu m emiss ion than non-Seyfert galaries have. Interactions do not affect appreci ably the 10 mu m emission of Seyfert galaxies. Their 10 mu m emission, which is quite weakly related to the X-ray emission, correlates well with the nuclear non-stellar near-infrared emission and with the IRAS 12 and 25 mu m band emissions, less well with the IRAS 60 mu m emissio n and even worse with the IRAS 100 mu m emission. The 100 mu m to 25 m u m global energy distribution flattens systematically with increasing 10 mu m luminosity. Seyferts 1 have, on average, greater 10 mu m lumi nosity than S2 have, but similar surface brightness and compactness. S eyferts 2 have steeper continuum spectra between 12 and 25 mu m than S eyferts 1 have. Our results favour thermal dust emission models for th e origin of the mid-infrared emission of Seyfert galaxies. Within the context of unified schemes of Seyfert galaxies, our findings support t he presence of a moderate amount of anisotropy in the 10 mu m emission and are consistent with the presence of Thomson optically thin obscur ing dust tori around Seyfert nuclei.