2000/02/23 by D. M. Crenshaw, S. B. Kraemer · 9 citations
Physics and Astronomy · #Acceleration #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Classical mechanics #Emission spectrum #Galaxies: Formation, Evolution, Phenomena #Galaxy #Geometry #Ion #Ionization #Kinematics #Line (geometry) #Outflow #Physics #Position angle #Radial velocity #Radiation pressure #Spectral line #Spectroscopy #Stars #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/312581
18 pages, Latex, includes 3 figures in postscript, to appear in the Astrophysical Journal Letters
arxiv created 2000/02/23 · openalex publication_date 2000/04/01 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We have determined the radial velocities of the [O iii]-emitting gas in the inner narrow-line region of the Seyfert 2 galaxy NGC 1068, along a slit at position angle 202 degrees, from STIS observations at a spatial resolution of 0&farcs;1 and a spectral resolving power of lambda&solm0;Deltalambda approximately 1000. We use these data to investigate the kinematics of the narrow-line region within 6&arcsec; ( approximately 430 pc) of the nucleus. The emission-line knots show evidence for radial acceleration to a projected angular distance of 1&farcs;7 in most cases, followed by deceleration that approaches the systemic velocity at a projected distance of approximately 4&arcsec;. We find that a simple kinematic model of biconical radial outflow can match the general trend of observed radial velocities. In this model, the emitting material is evacuated along the bicone axis, and the axis is inclined 5 degrees out of the plane of the sky. The acceleration of the emission-line clouds provides support for dynamical models that invoke radiation and/or wind pressure. We suggest that the deceleration of the clouds is due to their collision with a patchy and anistropically distributed ambient medium.