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Paper: AGN Narrow-Line Kinematics: Determining Inclinations via Outflows
Volume: 460, AGN Winds in Charleston
Page: 154
Authors: Fischer, T. C.; Crenshaw, D. M.; Kraemer, S. B.; Schmitt, H. R.; Turner, T. J.
Abstract: Active Galactic Nuclei (AGN) are axisymmetric systems in which their observed properties are strong functions of inclination with respect to our line of sight. However, except for a few special cases, the specific inclinations of individual AGN are unknown. We have developed a promising technique for determining the inclinations of nearby AGN by mapping the kinematics of their narrow-line regions (NLRs), which are easily resolved with Hubble Space Telescope (HST) [O III] imaging and long-slit spectra from STIS. Our studies indicate that NLR kinematics dominated by radial outflow can be fit with simple biconical outflow models that can be used to determine the inclination of the bicone axis, and hence the obscuring torus, with respect to our line of sight. Using inclinations determined from models of 17 individual AGN, we can for the first time assess the effect of inclination on other observable parameters in radio-quiet AGN, including the discovery of a distinct correlation between AGN inclination and X-ray column density. As our line of sight with respect to the bicone axis increases, the torus surrounding the AGN becomes closer to edge-on and we see a seamless increase in column density between Seyfert 1 and Seyfert 2 galaxies.
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