1. The slimming effect of advection on black-hole accretion flows
- Author
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Jean-Pierre Lasota, Marek A. Abramowicz, Rebecca Lynn Vieira, Aleksander Sadowski, Ramesh Narayan, Institut d'Astrophysique de Paris (IAP), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Copernicus Astronomical Center of the Polish Academy of Sciences (CAMK), Polish Academy of Sciences (PAN), Instituto de Astronomia, Geofísica e Ciências Atmosféricas [São Paulo] (IAG), Universidade de São Paulo (USP), MIT Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology (MIT), Harvard-Smithsonian Center for Astrophysics (CfA), Smithsonian Institution-Harvard University [Cambridge], Department of Physics, Göteborg University (GöTEBORG UNIVERSITY), University of Gothenburg (GU), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Universidade de São Paulo = University of São Paulo (USP), and Harvard University-Smithsonian Institution
- Subjects
Astrophysics::High Energy Astrophysical Phenomena ,FOS: Physical sciences ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,01 natural sciences ,Accretion disc ,accretion ,0103 physical sciences ,Radiative transfer ,Astrophysics::Solar and Stellar Astrophysics ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics ,Physics ,High Energy Astrophysical Phenomena (astro-ph.HE) ,010308 nuclear & particles physics ,Advection ,Astronomy and Astrophysics ,Analytical equations ,Torus ,Accretion (astrophysics) ,accretion disks / black hole physics ,Black hole ,Space and Planetary Science ,Astrophysics::Earth and Planetary Astrophysics ,Magnetohydrodynamics ,Astrophysics - High Energy Astrophysical Phenomena ,[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph] - Abstract
At super-Eddington rates accretion flows onto black holes have been described as slim (aspect ratio $H/R \lesssim 1$) or thick (H/R >1) discs, also known as tori or (Polish) doughnuts. The relation between the two descriptions has never been established, but it was commonly believed that at sufficiently high accretion rates slim discs inflate, becoming thick. We wish to establish under what conditions slim accretion flows become thick. We use analytical equations, numerical 1+1 schemes, and numerical radiative MHD codes to describe and compare various accretion flow models at very high accretion rates.We find that the dominant effect of advection at high accretion rates precludes slim discs becoming thick. At super-Eddington rates accretion flows around black holes can always be considered slim rather than thick., 8 pages, 5 figures. Astronomy & Astrophysics, in press
- Published
- 2016
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