X-Ray and Infrared Selected Active Galactic Nuclei. I. The Missing Edge-On Galaxies

Morphological classification and axial ratio measurements for a sample of 288 Seyfert Galaxies (SGs) are presented. Seyferts are predominantly spirals and we find a deficiency of edge-on objects of both classes Seyfert 1 and 2 in comparison with a sample of 1600 normal spirals. The data suggest that obscuration extends beyond the broad line region, and that the distribution of dust is flattened and coplanar with the disk of the parent galaxy. We propose a way to find the missing edge-on SGs on the basis of their infrared and x-ray emission. A sample of 144 IRAS galaxies lying inside or close to unidentified hard x-ray HEAO-1 sources is selected. Most of the target galaxies are in fact seen edge-on and we estimate that at least ~ 34 of them are obscured active galactic nuclei (AGN) associated with the x-ray sources.