Evolution of X-ray irradiation during the 1999–2000 outburst of the black hole binary XTE J1859 + 226

Kimura, Mariko; Done, Chris

doi:10.1093/mnras/sty2736

Evolution of X-ray irradiation during the 1999–2000 outburst of the black hole binary XTE J1859 + 226

Kimura, Mariko; Done, Chris

Authors

Mariko Kimura

Professor Christine Done chris.done@durham.ac.uk
Professor

Abstract

X-ray irradiation in X-ray binaries is thought to control the behaviour at the outer disc, which is observable mainly at optical wavelengths. It is generally parametrized phenomenologically, but it can also be predicted from theoretical models of irradiated discs and their coronae/winds. We test these models using five multiwavelength Hubble Space Telescopeand quasi simultaneous Rossi X-Ray Timing Explorer (RXTE) data sets from the black hole binary XTE J1859 + 226. These show how the reprocessed optical emission changes during outburst as the source fades from the very high/intermediate state at ∼0.4LEdd down through the high/soft state towards the transition to the hard state at ∼0.02LEdd. The models are able to reproduce the small change in reprocessing efficiency as the source flux decreases by a factor of two, and the spectrum softens from the very high/intermediate state to the bright high/soft state. However, the low luminosity high/soft state as well as the transition spectrum show more complex behaviour that is not well described by current models. We suggest the disc geometry has changed drastically during the outburst, probably due to tidal forces, and that the disc is no longer in steady state at the late stage of the outburst.

Citation

Kimura, M., & Done, C. (2019). Evolution of X-ray irradiation during the 1999–2000 outburst of the black hole binary XTE J1859 + 226. Monthly Notices of the Royal Astronomical Society, 482(1), 626-638. https://doi.org/10.1093/mnras/sty2736

Journal Article Type	Article
Acceptance Date	Oct 3, 2018
Online Publication Date	Oct 8, 2018
Publication Date	Jan 1, 2019
Deposit Date	Oct 5, 2018
Publicly Available Date	Oct 5, 2018
Journal	Monthly Notices of the Royal Astronomical Society
Print ISSN	0035-8711
Electronic ISSN	1365-2966
Publisher	Royal Astronomical Society
Peer Reviewed	Peer Reviewed
Volume	482
Issue	1
Pages	626-638
DOI	https://doi.org/10.1093/mnras/sty2736

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This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society © 2018 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.