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We present a simple kinematic model for the narrow-line region (NLR) of the Seyfert 1 galaxy NGC 4151, based on our previous observations of extended [O III] emission with the Space Telescope Imaging Spectrograph (STIS). The model is similar to a biconical radial outflow model developed for the Seyfert 2 galaxy NGC 1068, except that the bicone axis is tilted much more into our line of sight (40 degrees out of the plane of the sky instead of 5 degrees), and the maximum space velocities are lower (750 km/s instead of 1300 km/s. We find evidence for radial acceleration of the emission-line knots to a distance of 160 pc, followed by deceleration that approaches the systemic velocity at a distance of 290 pc (for a distance to NGC 4151 of 13.3 Mpc). Other similarities to the kinematics of NGC 1068 are: 1) there are a number of high-velocity clouds that are not decelerated, suggesting that the medium responsible for the deceleration is patchy, and 2) the bicone in NGC 4151 is at least partially evacuated along its axis. Together, these two Seyfert galaxies provide strong evidence for radial outflow (e.g., due to radiation and/or wind pressure) and against gravitational motion or expansion away from the radio jets as the principal kinematic component in the NLR.
We present the first results of the Hubble Space Telescope/Faint Object Camera long-slit spectroscopy of the inner 8 of the Narrow Line Region of NGC 4151 at a spatial resolution of 0.029. The emission gas is characterized by an underlying general or
We present subarcsecond resolution mid infrared images of NGC 4151 at 10.8 micron and 18.2 micron. These images were taken with the University of Florida mid-IR camera/spectrometer OSCIR at the Gemini North 8-m telescope. We resolve emission at both
We present the first extensive study of the coronal line variability in an active galaxy. Our data set for the nearby source NGC 4151 consists of six epochs of quasi-simultaneous optical and near-infrared spectroscopy spanning a period of about eight
We present a study of the distribution of [O III] $lambda$5007 and [O II] $lambda$3727 emission in the Narrow Line Region (NLR) of the Seyfert 1 galaxy NGC 4151. While the NLR of NGC 4151 exhibits an overall structure consistent with the unified mode