Kinematics of the Narrow-Line Region in the Seyfert 2 Galaxy NGC 1068: Dynamical Effects of the Radio Jet

Abstract

We present a study of high-resolution long-slit spectra of the narrow-line region (NLR) in NGC 1068 obtained with the Space Telescope Imaging Spectrograph aboard the Hubble Space Telescope (HST). The spectra were retrieved from the Multimission Archive at the Space Telescope Science Institute obtained from two visits and seven orbits of HST time. We also obtained MERLIN radio maps of the center of NGC 1068 to examine the dependence of the NLR cloud velocities on the radio structure. The radial velocities and velocity dispersions of the bright NLR clouds appear to be unaffected by the radio knots, indicating that the radio jet is not the principal driving force on the outflowing NLR clouds. However, the velocities of the fainter NLR clouds are split near knots in the jet, indicating a possible interaction. Biconical outflow models were generated to match the data and for comparison to previous models done with lower dispersion observations. The general trend is an increase in radial velocity roughly proportional to distance from the nucleus followed by a linear decrease after roughly 100 pc similar to that seen in other Seyfert galaxies, indicating common acceleration and deceleration mechanisms.