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J.R. Ruiz (IACS, CUA), S.B. Kraemer, (CUA, NASA's GSFC ), D.M. Crenshaw (Georgia State University (GSU))
Using a set of new Space Telescope Imaging Spectrograph (STIS) slitless spectra of 10 Seyfert galaxies, we determine radial velocities for the narrow-line region (NLR) gas in these galaxies out to a radius of a few kiloparsecs in each galaxy. We have modeled the velocity profiles in order to constrain the kinematics and distribution of the emission-line gas, and these profiles will be presented.
The radial velocity measurements (as a function of position out from the nucleus) indicate several general trends including: blueshifts and redshifts on either side of the nuclei of the galaxies, steep velocity rises from systemic up to several hundred kilometers per second taking place in the inner tenths of kiloparsecs from the nuclei, and lower velocities out to the limits of our observations and uneven velocity amplitudes on each side of the nuclei.
From the kinematic modeling, we find strong evidence that the gas exists in a partially filled bicone, is accelerated radially away from the nucleus out to some distance, then decelerated. However, in several of our objects, we cannot rule out a model where the gas is accelerated tangentially away from the NLR axis, as if a linear radio jet were expanding out from its axis, pushing out the NLR gas. The physical implications of these models will be discussed.