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(No) dynamical constraints on the mass of the black hole in two ULXs

Roberts, T.P.; Gladstone, J.C.; Goulding, A.D.; Swinbank, A.M.; Ward, M.J.; Goad, M.R.; Levan, A.J.


J.C. Gladstone

A.D. Goulding

A.M. Swinbank

M.J. Ward

M.R. Goad

A.J. Levan


We present the preliminary results of two Gemini campaigns to constrain the mass of the black hole in an ultraluminous X-ray source (ULX) via optical spectroscopy. Pilot studies of the optical counterparts of a number of ULXs revealed two candidates for further detailed study, based on the presence of a broad He II 4686 Å emission line. A sequence of 10 long-slit spectra were obtained for each object, and the velocity shift of the ULX counterpart measured. Although radial velocity variations are observed, they are not sinusoidal, and no mass function is obtained. However, the broad He II line is highly variable on timescales shorter than a day. If associated with the reprocessing of X-rays in the accretion disc, its breadth implies that the disc must be close to face-on.


Roberts, T., Gladstone, J., Goulding, A., Swinbank, A., Ward, M., Goad, M., & Levan, A. (2011). (No) dynamical constraints on the mass of the black hole in two ULXs. Astronomical Notes, 332(4), 398-401.

Journal Article Type Article
Publication Date May 1, 2011
Deposit Date Jan 30, 2012
Publicly Available Date Jan 24, 2014
Journal Astronomische Nachrichten
Print ISSN 0004-6337
Electronic ISSN 1521-3994
Publisher Wiley
Peer Reviewed Peer Reviewed
Volume 332
Issue 4
Pages 398-401
Keywords Accretion discs, Binaries, Spectroscopic, Black hole physics, X-rays.


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