Please use this identifier to cite or link to this item: http://hdl.handle.net/2381/25192
Title: Accretion rates and beaming in ultraluminous X-ray sources
Authors: King, A. R.
First Published: 1-Mar-2008
Publisher: Royal Astronomical Society (RAS)
Citation: Monthly Notices of the Royal Astronomical Society: LETTERS, 2008, 385 (1)
Abstract: I show that extreme beaming factors b are not needed to explain ultraluminous X-ray sources (ULXs) as stellar-mass binaries. For neutron-star accretors, one typically requires b∼ 0.13, and for black holes almost no beaming (b∼ 0.8). The main reason for the high apparent luminosity is the logarithmic increase in the limiting luminosity for super-Eddington accretion. The required accretion rates are explicable in terms of thermal-time-scale mass transfer from donor stars of mass 6–10 M⊙, or possibly transient outbursts. Beaming factors ≲0.1 would be needed to explain luminosities significantly above 1040L40 erg s−1, but these requirements are relaxed somewhat if the accreting matter has low hydrogen content.
DOI Link: 10.1111/j.1745-3933.2008.00444.x
ISSN: 1745-3933
Links: http://hdl.handle.net/2381/25192
http://mnrasl.oxfordjournals.org/content/385/1/L113
Version: Publisher Version
Status: Peer-reviewed
Type: Journal Article
Rights: This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2008 the authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. Deposited with reference to the publisher’s archiving policy available on the SHERPA/RoMEO website.
Appears in Collections:Published Articles, Dept. of Physics and Astronomy

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