HST Long Slit Spectroscopy of NGC 1068 and NGC 4151

Abstract

NGC 1068 annd NGC 4151 are Seyfert Galaxies, the most common type of active galaxy, in which a luminous nucleus is powered by accretion onto a massive black hole at its center. Seyfert galaxies are known to exhibit high velocity outflows from their nuclei, however, the driving mechanisms are not fully understood. Typically, they are attributed to a nuclear wind, which blows material away from the nucleus in a bi-polar conical flow, or to interactions with a radio jet, which would expel material perpendicularly away from the jet axis. Using spectroscopic observations taken by the Hubble Space Telescope we are studying the structure and motion of the ionized gas clouds in these two objects, to understand the nature and origin of the flow. We compare our data with models of the gas kinematics to identify regions in these galaxies that display the signatures of a nuclear wind, jet-gas interaction, or both. We also measure the relative strengths of specific emission lines produced by these clouds to provide information about the ionization state of the clouds themselves. Preliminary results show high velocity gas flows in both galaxies and indicate that both jet and wind processes may be operating.