Jean-Pierre Lasota (IAP, N. Copernicus Astronomical Center)
Thursday November 12th - 11am
IPAG Seminar Room - IPAG
According to a widely spread prejudice accretion onto compact bodies cannot be super-Eddington either in luminosity or in accretion rate. I will go over the old but generally ignored theoretical argument (Begelman 1979) showing that there is no limit on the accretion rate onto a black hole and present various astrophysical situations in which accretion luminosity can be super-Eddington. These theoretical considerations will be followed by a discussion of observations which clearly show the evidence for super-Eddington accretion flows. I will argue that most (if not all) so-called ultra luminous X-ray sources (ULXs) contain stellar-mass compact objects (neutron stars or black holes) and argue that this is also the case for hyper-luminous X-ray sources, in particular the celebrated source HLX-1 in the galaxy ESO 243-49.
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