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Date and Time of the Query: 2019-06-19 T16:23:15 PDT
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For refcode 2007ApJ...657..159B:
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2007ApJ...657..159B The Eddington Ratios in Seyfert 2 Galaxies with and without Hidden Broad-Line Regions W. Bian and Q. Gu Abstract. Using a large sample of 90 Seyfert 2 galaxies (Sy2s) with spectropolarimetric observations, we test the suggestion that the presence of hidden broad-line regions (HBLRs) in Sy2s depends upon the Eddington ratio. The stellar velocity dispersion and extinction-corrected [O III] luminosity are used to derive the masses of central supermassive black holes and the Eddington ratio. We find that (1) below an Eddington ratio threshold of 10^-1.37^, all of the objects but one are non-HBLR Sy2s, while at higher Eddington ratios there is no obvious distinction in the Eddington ratio and black hole mass distributions between Sy2s with and without HBLRs; (2) almost no low-luminosity Sy2s (e.g., L_[OIII]_<10^41^ ergs s^-1^) show HBLRs, regardless of the column density of neutral hydrogen; (3) for high luminosities, the possibility of detecting HBLR Sy2s is almost the same as that for non-HBLR Sy2s; and (4) when considering only Compton-thin Sy2s with higher [O III] luminosity (>10^41^ ergs s^-1^), the detectability of HBLRs is very high, ~85%. These results suggest that AGN luminosity plays a major role in the failure to detect HBLRs in low-luminosity Sy2s, while for high-luminosity Sy2s the detectability of HBLRs depends not only upon the AGN activity, but also upon the torus obscuration. Key words: Galaxies: Active, Galaxies: Seyfert, Polarization
Retrieve 90 NED objects in this reference.
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