The disk–torus system in active galactic nuclei: possible evidence of highly spinning black holes

We study the ratio R between the luminosity of the torus and that of the accretion disk, inferred from the relativistic model KERRBB for a sample of approximately 2000 luminosity-selected radio-quiet Type I active galactic nuclei from the Sloan Digital Sky Survey catalog. We find a mean ratio R  ≈ 0...

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Bibliographic Details
Published inAstronomy and astrophysics (Berlin) Vol. 656; p. A96
Main Authors Campitiello, Samuele, Celotti, Annalisa, Ghisellini, Gabriele, Sbarrato, Tullia
Format Journal Article
LanguageEnglish
Published Heidelberg EDP Sciences 01.12.2021
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Summary:We study the ratio R between the luminosity of the torus and that of the accretion disk, inferred from the relativistic model KERRBB for a sample of approximately 2000 luminosity-selected radio-quiet Type I active galactic nuclei from the Sloan Digital Sky Survey catalog. We find a mean ratio R  ≈ 0.8 and a considerable number of sources with R  ≳ 1. Our statistical analysis regarding the distribution of the observed ratios suggests that the largest values might be linked to strong relativistic effects due to a large black hole spin ( a  > 0.8), despite the radio-quiet nature of the sources. The mean value of R sets a constraint on the average torus aperture angle (in the range 30° < θ T  < 70°) and, for about one-third of the sources, the spin must be a  > 0.7. Moreover, our results suggest that the strength of the disk radiation (i.e., the Eddington ratio) could shape the torus geometry and the relative luminosity ratio R . Given the importance of the involved uncertainties on this statistical investigation, an extensive analysis and discussion have been made to assess the robustness of our results.
ISSN:0004-6361
1432-0746
DOI:10.1051/0004-6361/202141602