An Ionization Cone and Dusty Disk in Markarian 348: The Obscuring Torus Revealed?

Abstract

We report on optical emission-line and near-infrared continuum images of the Seyfert 2 galaxy Mrk 348 (NGC 262). The optical images reveal a well-defined region of highly ionized gas aligned approximately north-south (i.e., along the radio axis), possibly in the form of a bicone. In addition, there is a red linear structure in the infrared continuum, oriented perpendicular to this axis and approximately 1 kpc in extent. We examine the possibility that this latter structure is emission from hot (~750 K) dust in a disk or torus viewed approximately edge-on. This disk may comprise the outer parts of the "dusty torus" postulated in schemes to unify the two types of Seyfert galaxies. The featureless continuum may come from hot stars associated with a 4 kpc diameter ring of H II regions surrounding the nucleus.