LOW-LUMINOSITY AND OBSCURED SEYFERT NUCLEI IN NEARBY GALAXIES

We discuss the Seyfert galaxies in the Revised Shapley-Ames catalog (B-T < 13.31) and in three extensions to it (B-T < 13.4). The sample contains 91 relatively nearby Seyfert galaxies. The proximity of the objects reduces the dilution of their nuclear spectra by the host galaxy light. As a consequence, biases against low-luminosity nuclei (relative to the host) and against edge-on galaxies are reduced compared with other samples of Seyfert galaxies. From this sample, we set a lower limit of 5% to the portion of galaxies with Seyfert nuclei; completeness arguments could support a percentage as high as 16%. We find type 2 Seyfert nuclei (i.e., types 1.8 + 1.9 + 2) to be 4 times more numerous than type 1 ones (types 1 + 1.2 + 1.5). Seyfert nuclei of types 1 + 1.2 + 1.5 are mostly found in face-on galaxies, while intermediate nuclei of types 1.8 + 1.9 are mostly found in edge-on hosts. These results suggest that most of the intermediate type Seyfert nuclei are type 1 nuclei seen through a 100 pc-scale torus coplanar with the galactic disk and not type 1 nuclei partially obscured by an inner parsec-scale torus.