Skip to main content

Research Repository

Advanced Search

The soft component and the iron line as signatures of the disc inner radius in Galactic black hole binaries

Kolehmainen, M.; Done, C.; Díaz Trigo, M.

The soft component and the iron line as signatures of the disc inner radius in Galactic black hole binaries Thumbnail


Authors

M. Kolehmainen

M. Díaz Trigo



Abstract

The inner radius of the accretion disc around a black hole in the low/hard state can be measured in one of two ways. First, via the extent of broadening of the iron emission line, and secondly, from the luminosity and temperature of the weak soft component seen in this state, assuming it is the disc. We use both of these methods on all the low/hard state spectra taken in timing mode of XMM–Newton's EPIC-pn. We find that the two methods are not consistent with each other, and the difference is not always in a single direction. The two methods are neither model independent, nor are they independent of current calibration issues. We find that the remaining small residuals in the EPIC-pn timing mode response at the ≤3 per cent level can have a dramatic effect on the fit parameters for the reflected spectrum. There is also a mismatch in cross-calibration with RXTE, which makes it difficult to use simultaneous data to extend the bandpass of the spectral fits. Nonetheless, it is clear from the data that the iron line is noticeably broader and stronger at higher L/LEdd, which is consistent with the truncated disc models. We also show that it is likely that the soft component changes character, from a stable component consistent with a truncated disc at high L/LEdd, to a variable one with much smaller radius at low L/LEdd. This adds to growing evidence for a complex soft component in the low/hard state, possibly resulting from clumps torn from the edge of the truncated disc.

Citation

Kolehmainen, M., Done, C., & Díaz Trigo, M. (2014). The soft component and the iron line as signatures of the disc inner radius in Galactic black hole binaries. Monthly Notices of the Royal Astronomical Society, 437(1), 316-326. https://doi.org/10.1093/mnras/stt1886

Journal Article Type Article
Acceptance Date Oct 2, 2013
Online Publication Date Oct 31, 2013
Publication Date Jan 1, 2014
Deposit Date Mar 16, 2016
Publicly Available Date Mar 29, 2024
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 437
Issue 1
Pages 316-326
DOI https://doi.org/10.1093/mnras/stt1886
Related Public URLs http://adsabs.harvard.edu/abs/2014MNRAS.437..316K

Files

Published Journal Article (898 Kb)
PDF

Copyright Statement
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.





You might also like



Downloadable Citations