The Narrow-Line Regions of LINERs as Resolved with the Hubble Space Telescope1

Low-ionization nuclear emission-line regions (LINERs) exist in the nuclei of a large fraction of luminous galaxies, but their connection with the active galactic nucleus (AGN) phenomenon has remained elusive. We present Hubble Space Telescope (HST) narrowband ([O III]λ5007 and Hα+[N II]) emission-line images of the central regions of 14 galaxies with LINER nuclei. This is the first such study of a sizable sample of LINERs at HST resolution. The compact, ∼1′′-scale, unresolved emission which dominates the line flux in ground-based observations of these LINERs is mostly resolved in the HST images. The bulk of the Hα and [O III] emission comes from regions with sizes of tens to hundreds of parsecs. The resolved emission comes from a combination of knots, filaments, and diffuse gas whose morphology differs from galaxy to galaxy. Most of the galaxies do not show clear linear structures or ionization cones analogous to those often seen in Seyfert galaxies. An exception is NGC1052, the prototypical LINER, in Based on observations with the Hubble Space Telescope which is operated by AURA, Inc., under NASA contract NAS 5-26555.