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Orientation effects on the near-infrared broad-band emission of quasars

Bisogni, Susanna; Lusso, Elisabeta; Marconi, Alessandro; Risaliti, Guido

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Authors

Susanna Bisogni

Alessandro Marconi

Guido Risaliti



Abstract

We recently proposed the equivalent width (EW) of the narrow [O III]5007 Å emission line as an orientation indicator for active galactic nuclei. We tested this method on about 12 300 optically selected broad-line quasars from the SDSS seventh Data Release at redshift z < 0.8 and with full width at half-maximum values of broad emission lines (H α, H β, and Mg II) larger than 2000 km s−1. We now examine their spectral energy distributions (SEDs) using broad-band photometry from the near-infrared to the ultraviolet to look for variations in the overall shape as a function of the EW[O III]. We find that quasars with low EW[O III] values (close to face-on position) have flatter near-infrared SEDs with respect to sources with high EW[O III] values (almost edge-on). Moreover, quasars with high EW[O III] values show a factor of ∼2 lower emission in the UV to quasars with low EW[O III] values. Our findings indicate that the torus is clumpy and, on average, co-axial with the accretion disc and broad-line region, in agreement with the most recent theoretical models for the obscuring torus.

Citation

Bisogni, S., Lusso, E., Marconi, A., & Risaliti, G. (2019). Orientation effects on the near-infrared broad-band emission of quasars. Monthly Notices of the Royal Astronomical Society, 485(1), 1405-1411. https://doi.org/10.1093/mnras/stz495

Journal Article Type Article
Acceptance Date Feb 14, 2019
Online Publication Date Feb 17, 2019
Publication Date May 31, 2019
Deposit Date May 29, 2019
Publicly Available Date May 29, 2019
Journal Monthly Notices of the Royal Astronomical Society
Print ISSN 0035-8711
Electronic ISSN 1365-2966
Publisher Royal Astronomical Society
Peer Reviewed Peer Reviewed
Volume 485
Issue 1
Pages 1405-1411
DOI https://doi.org/10.1093/mnras/stz495

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Copyright Statement
© 2019 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society.





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