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The Causal Connection Between Disc and Power-Law Variability in Hard State Black Hole X-Ray BinariesWe use the XMM-Newton EPIC-pn instrument in timing mode to extend spectral time-lag studies of hard state black hole X-ray binaries into the soft X-ray band. \Ve show that variations of the disc blackbody emission substantially lead variations in the power-law emission, by tenths of a second on variability time-scales of seconds or longer. The large lags cannot be explained by Compton scattering but are consistent with time-delays due to viscous propagation of mass accretion fluctuations in the disc. However, on time-scales less than a second the disc lags the power-law variations by a few ms, consistent with the disc variations being dominated by X-ray heating by the power-law, with the short lag corresponding to the light-travel time between the power-law emitting region and the disc. Our results indicate that instabilities in the accretion disc are responsible for continuum variability on time-scales of seconds or longer and probably also on shorter time-scales.
Document ID
20110011238
Acquisition Source
Goddard Space Flight Center
Document Type
Preprint (Draft being sent to journal)
Authors
Uttley, P.
(Southampton Univ. United Kingdom)
Wilkinson, T.
(Southampton Univ. United Kingdom)
Cassatella, P.
(Southampton Univ. United Kingdom)
Wilms, J.
(Erlangen-Nuernberg Univ. Bamberg, Germany)
Pottschimdt, K.
(Maryland Univ. Baltimore County Baltimore, MD, United States)
Hanke, M.
(Erlangen-Nuernberg Univ. Bamberg, Germany)
Boeck, M.
(Erlangen-Nuernberg Univ. Bamberg, Germany)
Date Acquired
August 25, 2013
Publication Date
January 1, 2010
Subject Category
Astronomy
Funding Number(s)
CONTRACT_GRANT: NNG06E090A
CONTRACT_GRANT: 50 OR 0808
CONTRACT_GRANT: 50 OR 0701
CONTRACT_GRANT: ITN 215212
Distribution Limits
Public
Copyright
Other

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