Obscuration in the Host Galaxies of Soft X-ray Selected Seyferts

Abstract

We define a new sample of 96 low-redshift (z<0.1), soft X-ray selected Seyferts from the catalog of the Einstein Slew Survey (Elvis etal. 1992, Plummer et al. 1994). We probe the geometry and column depth of obscuring material in the host-galaxy disks using galaxian axial ratios determined mainly from the Digitized Sky Survey. The distribution of host-galaxy axial ratios clearly shows a bias against edge-on spirals, confirming the existence of a geometrically thick layer of obscuring material in the host-galaxy planes. Soft X-ray selection recovers some of the edge-on objects missed in UV and visible surveys but still results in 30% incompleteness for Type 1's. We speculate that thick rings of obscuring material like the ones we infer for these Seyferts might be commonly present in early type spirals, sitting at the Inner Lindblad Resonances of the nonaxisymmetric potentials of the host galaxies.