Spectral and Fourier analyses of X-ray quasi-periodic oscillations in accreting black holes

Sobolewska, M.A.; Zycki, P.T.

doi:10.1111/j.1365-2966.2006.10489.x

Spectral and Fourier analyses of X-ray quasi-periodic oscillations in accreting black holes

Sobolewska, M.A.; Zycki, P.T.

Authors

M.A. Sobolewska

P.T. Zycki

Abstract

We study energy dependencies of quasi-periodic oscillations (QPOs) from a number of black hole X-ray binaries. The selected sources were observed by RXTE at time periods close to state transitions and showed QPOs in the 1–10 Hz range. We have constructed QPO rms energy spectra, which provide information about underlying physical process leading to QPO generation. These spectra show an interesting anticorrelation with the time-averaged spectra. The QPO rms spectra are harder than the time-averaged spectra when the latter are soft, while they are softer than the time-averaged spectra when the latter are hard. We then discuss these observational results in the context of simple spectral variability models. Hard QPO spectra can be produced by quasi-periodic modulations of the heating rate of the Comptonizing plasma, while soft QPO spectra result from modulations of the cooling rate by soft photons.

Citation

Sobolewska, M., & Zycki, P. (2006). Spectral and Fourier analyses of X-ray quasi-periodic oscillations in accreting black holes. Monthly Notices of the Royal Astronomical Society, 370(1), 405-414. https://doi.org/10.1111/j.1365-2966.2006.10489.x

Journal Article Type	Article
Publication Date	2006-07
Deposit Date	May 2, 2008
Publicly Available Date	May 2, 2008
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	370
Issue	1
Pages	405-414
DOI	https://doi.org/10.1111/j.1365-2966.2006.10489.x
Keywords	Accretion discs, Instabilities, Radiation thermal mechanisms, X-rays.