NASA/IPAC EXTRAGALACTIC DATABASE
Date and Time of the Query: 2019-08-18 T02:45:29 PDT
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For refcode 2015ApJ...806..127D:
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Copyright by American Astronomical Society. Reproduced by permission
2015ApJ...806..127D Insights on the Dusty Torus and Neutral Torus from Optical and X-Ray Obscuration in a Complete Volume Limited Hard X-Ray AGN Sample Davies, R. I.; Burtscher, L.; Rosario, D.; Storchi-Bergmann, T.; Contursi, A.; Genzel, R.; Gracia-Carpio, J.; Hicks, E.; Janssen, A.; Koss, M.; Lin, M.-Y.; Lutz, D.; Maciejewski, W.; Muller-Sanchez, F.; Orban de Xivry, G.; Ricci, C.; Riffel, R.; Riffel, R. A.; Schartmann, M.; Schnorr-Muller, A.; Sternberg, A.; Sturm, E.; Tacconi, L.; Veilleux, S. Abstract. We describe a complete volume limited sample of nearby active galaxies selected by their 14--195 keV luminosity, and outline its rationale for studying the mechanisms regulating gas inflow and outflow. We also describe a complementary sample of inactive galaxies, selected to match the host galaxy properties. The active sample appears to have no bias in terms of active galactic nucleus (AGN) type, the only difference being the neutral absorbing column, which is two orders of magnitude greater for the Seyfert 2s. In the luminosity range spanned by the sample, log {{L}_14-195 keV_}[erg\{{s}^-1^}]=42.4--43.7, the optically obscured and X-ray absorbed fractions are 50%--65%. The similarity of these fractions to more distant spectroscopic AGN samples, although over a limited luminosity range, suggests that the torus does not strongly evolve with redshift. Our sample confirms that X-ray unabsorbed Seyfert 2s are rare, comprising not more than a few percent of the Seyfert 2 population. At higher luminosities, the optically obscured fraction decreases (as expected for the increasing dust sublimation radius), but the X-ray absorbed fraction changes little. We argue that the cold X-ray absorption in these Seyfert 1s can be accounted for by neutral gas in clouds that also contribute to the broad-line region (BLR) emission, and suggest that a geometrically thick neutral gas torus co-exists with the BLR and bridges the gap to the dusty torus. Key words: galaxies: active, galaxies: nuclei, galaxies: Seyfert, X-rays: galaxies
Retrieve 39 NED objects in this reference.
Please click here for ADS abstract

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