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http://hdl.handle.net/20.500.12386/27012
Title: | EW[OIII] as an orientation indicator for quasars: implications for the torus | Authors: | Bisogni, Susanna Marconi, Alessandro RISALITI, Guido LUSSO, ELISABETA |
Issue Date: | 2017 | Journal: | FRONTIERS IN ASTRONOMY AND SPACE SCIENCES | Number: | 4 | First Page: | 48 | Abstract: | We present an analysis of the average spectral properties of 12,000 SDSS quasars as a function of accretion disc inclination, as measured from the equivalent width of the [O III] 5007Å line. The use of this indicator on a large sample of quasars from the SDSS DR7 has proven the presence of orientation effects on the features of UV/optical spectra, confirming the presence of outflows in the NLR gas and that the geometry of the BLR is disc-like. Relying on the goodness of this indicator, we are now using it to investigate other bands/components of AGN. Specifically, the study of the UV/optical/IR SED of the same sample provides information on the obscuring “torus”. The SED shows a decrease of the IR fraction moving from face-on to edge-on sources, in agreement with models where the torus is co-axial with the accretion disc. Moreover, the fact we are able to observe the broad emission lines also in sources in an edge-on position, suggests that the torus is rather clumpy than smooth as in the Unified Model. The behaviour of the SED as a function of EW[OIII] is in agreement with the predictions of the clumpy torus models as well. | URI: | http://hdl.handle.net/20.500.12386/27012 | URL: | https://www.frontiersin.org/articles/10.3389/fspas.2017.00048/full | ISSN: | 2296-987X | DOI: | 10.3389/fspas.2017.00048 | Bibcode ADS: | 2017FrASS...4...48B | Fulltext: | open |
Appears in Collections: | 1.01 Articoli in rivista |
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5_BisogniProceeding2.pdf | PDF editoriale | 1.07 MB | Adobe PDF | View/Open |
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