Dust lanes causing structure in the extended narrow-line region of early-type Seyfert galaxies

We construct near-infrared to visible broadband NICMOS/WFPC color maps for four early-type Seyfert galaxies with S-shaped or one-sided ionization cone s. We find that dust lanes are near or connected to many of the features se en in the [O III] and H alpha + [N III] line emission maps. This suggests t hat much of the structure of line emission in these ionization cones is det ermined by the distribution of ambient dense galactic gas. Spiral arms, dus t lanes caused by bars, or gaseous warps provide dense gas, which when illu minated by a conical beam of ultraviolet photons can result in the complica ted line emission morphologies observed.