Fast variability as a probe of the smallest regions around accreting black holes

Axelsson, M.; Hjalmarsdotter, L.; Done, C.

doi:10.1093/mnras/stt315

Fast variability as a probe of the smallest regions around accreting black holes

Axelsson, M.; Hjalmarsdotter, L.; Done, C.

Authors

M. Axelsson

L. Hjalmarsdotter

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

Abstract

We extract the spectra of the fastest variability (above 10 Hz) from the black hole XTE J1550−564 during a transition from hard to soft state on the rise to outburst. We confirm previous results that the rapid variability contains no significant disc component despite this being strongly present in the total spectrum of the softer observations. We model ionized reflection significantly better than previous work, and show that this is also suppressed in the rapid variability spectrum compared to the total emission. This is consistent with the fast variability having its origin in a hot inner flow close to the black hole rather than in the accretion disc or in a corona above it. However, the rapid variability spectrum is not simply the same as the total Comptonized emission. It is always significantly harder, by an amount which increases as the spectrum softens during the outburst. This adds to evidence from time lags that the Comptonization region is inhomogeneous, with harder spectra produced closest to the black hole, the same region which produces the fastest variability.

Citation

Axelsson, M., Hjalmarsdotter, L., & Done, C. (2013). Fast variability as a probe of the smallest regions around accreting black holes. Monthly Notices of the Royal Astronomical Society, 431(2), 1987-1994. https://doi.org/10.1093/mnras/stt315

Journal Article Type	Article
Acceptance Date	Feb 18, 2013
Online Publication Date	Mar 15, 2013
Publication Date	May 11, 2013
Deposit Date	Mar 16, 2016
Publicly Available Date	Mar 18, 2016
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	431
Issue	2
Pages	1987-1994
DOI	https://doi.org/10.1093/mnras/stt315
Related Public URLs	http://adsabs.harvard.edu/abs/2013MNRAS.431.1987A

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This article has been accepted for publication in Monthly notices of the Royal Astronomical Society ©: 2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.