1997/06/16 by Robert Simcoe, Robert A. Simcoe, K. K. McLeod +4
Physics and Astronomy · #Astrophysical Phenomena and Observations #Astrophysics and Cosmic Phenomena #Galaxies: Formation, Evolution, Phenomena #astro-ph
paper · pdf · doi:10.1086/304819
14 pages including 2 tables and 3 eps figures, aas2pp4.sty, to appear in ApJ
arxiv created 1997/06/16 · openalex publication_date 1997/11/10 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/04
We define a new sample of 96 low-redshift ( z < 0.1), soft X-ray-selected Seyfert galaxies from the catalog of the Einstein Slew Survey. We probe the geometry and column depth of obscuring material in the host-galaxy disks using galactic axial ratios determined mainly from the Digitized Sky Survey. The distribution of host-galaxy axial ratios clearly shows a bias against edge-on spirals, which confirms 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 nuclei. We speculate that thick rings of obscuring material such as the ones we infer for these Seyfert galaxies might be commonly present in early-type spirals, sitting at the inner Lindblad resonances of the nonaxisymmetric potentials of the host galaxies.