(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.

Abstract

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.

Citation

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. https://doi.org/10.1002/asna.201011508

• 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
• DOI: https://doi.org/10.1002/asna.201011508
• Keywords: Accretion discs, Binaries, Spectroscopic, Black hole physics, X-rays.