Spatially Resolved Ultraviolet Spectra of the High-Velocity Nuclear Outflow of NGC 1068

Abstract

We present ultraviolet emission-line maps of the narrow-line region (NLR) of NGC 1068. The maps span 115-318 nm, the biconical ionization cone, and several posited jet-ISM interactions, and the compact knots whose optical spectra we reported previously resemble kinematically the quasar associated absorption line systems. Across the NLR, we find that ultraviolet flux ratios are consistent with photoionization, not shock excitation, even for gas blueshifted abruptly to 3000 km s^-1 relative to galaxy systemic velocity or for gas projected near the radio jet. The knots may be radiatively accelerated, photoablated fragments of molecular clouds.

Based on observations made with the NASA Hubble Space Telescope (HST), obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. These observations are associated with proposal ID GO-7353.