Dust Morphology of Hidden Broad-Line Region and Non-Hidden Broad-Line Region Seyfert 2 Galaxies

Abstract

We investigate the nuclear dust properties of hidden broad-line region (HBLR) and non-HBLR Seyfert 2 galaxies. Optical images obtained from the Hubble Space Telescope for a selected sample of HBLR and non-HBLR Seyfert 2 galaxies are fitted with the Galfit package to probe the inner structures of these galaxies within the central 1 kpc regions. Most of the galaxies show complicated dust features in these regions. However, the dust morphology shows no significant difference between the HBLR and non-HBLR Seyfert 2 galaxies. Dust masses inside the 1 kpc nuclear regions (M_1kpc) are estimated from the obscuration levels in the central regions of these galaxies. We compare our results with other observed properties, including [O III], far-infrared, and radio emission. We find that the HBLR and non-HBLR Seyfert 2 galaxies show different near-infrared colors and M_1kpc-FIR correlations, indicating that these two classes of Seyfert 2 galaxies are dominated by different emission mechanisms. We suggest that they are intrinsically different and cannot be explained by the standard unification model.