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Broad absorption features in wind-dominated ultraluminous X-ray sources?

Middleton, Matthew J. and Walton, Dominic J. and Roberts, Timothy P. and Heil, Lucy (2014) Broad absorption features in wind-dominated ultraluminous X-ray sources? Monthly Notices of the Royal Astronomical Society, 438 (1). L51-L55. ISSN 0035-8711. doi:10.1093/mnrasl/slt157.

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The luminosities of ultraluminous X-ray sources (ULXs) require an exotic solution with either supercritical accretion modes on to stellar-mass black holes or subcritical accretion on to intermediate-mass black holes (IMBHs) being invoked. Discriminating between the two is non-trivial due to the present lack of a direct mass measurement. A key expectation of the supercritical mode of accretion is the presence of powerful radiatively driven winds. Here we analyse XMM–Newton data from NGC 5408 X-1 and NGC 6946 X-1 and find that strong soft residuals present in the X-ray spectra can be reconciled with broadened, blueshifted absorption by a partially ionized, optically thin phase of this wind. We derive initial values for the physical parameters of the wind; we also discuss other possible origins for the observed features.

Item Type:Article
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URLURL TypeDescription DOIArticle Paper
Middleton, Matthew J.0000-0002-8183-2970
Walton, Dominic J.0000-0001-5819-3552
Roberts, Timothy P.0000-0001-8252-6337
Alternate Title:Broad absorption features in wind-dominated ULXs?
Additional Information:© 2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2013 October 30. Received 2013 October 18; in original form 2013 September 12. First published online: December 11, 2013. The authors thank Tim Kallmann for insights into the use of XSTAR2XSPEC. MJM acknowledges support via a Marie Curie FP7 Postdoctoral scholarship. TPR was funded as part of the STFC consolidated grant ST/K000861/1. This work is based on observations obtained with XMM–Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA. We thank the anonymous referee for useful suggestions.
Funding AgencyGrant Number
Marie Curie FP7 Postdoctoral scholarshipUNSPECIFIED
STFC consolidated grantST/K000861/1
Subject Keywords: accretion, accretion discs; black hole physics; X-rays: binaries
Issue or Number:1
Record Number:CaltechAUTHORS:20140228-085800142
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Official Citation: Matthew J. Middleton, Dominic J. Walton, Timothy P. Roberts, and Lucy Heil Broad absorption features in wind-dominated ultraluminous X-ray sources? MNRAS first published online December 11, 2013 doi:10.1093/mnrasl/slt157
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:44050
Deposited By: Ruth Sustaita
Deposited On:28 Feb 2014 17:35
Last Modified:10 Nov 2021 16:47

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