Volume 403, Number 1, May III 2003
|Page(s)||L15 - L18|
|Published online||29 April 2003|
Letter to the Editor
Energy and time-lag spectra of galactic black-hole X-ray sources in the low/hard state
G.A.C.E, ICMUV, Universitat de Valencia, 46071 Paterna-Valencia, Spain
2 Foundation for Research and Technology-Hellas, 711 10 Heraklion, Crete, Greece
3 University of Crete, Physics Department, PO Box 2208, 710 03 Heraklion, Crete, Greece
Corresponding author: P. Reig, email@example.com
Accepted: 25 March 2003
Most, probably all, accreting binaries that are believed to contain a black-hole emit radio waves when they are in the low/hard state. Whenever this radio emission has been resolved, a jet-like structure has become apparent. We propose that Compton upscattering of low-energy photons in the jet can explain both the energy spectra and the time lags versus Fourier frequency observed in the low/hard state of black-hole systems. The soft photons originate in the inner part of the accretion disk. We have performed Monte Carlo simulations of Compton upscattering in a jet and have found that for a rather wide range of values of the parameters we can obtain power-law high-energy X-ray spectra with photon-number index in the range 1.5–2 and power-law time lags versus Fourier frequency with index ~0.7. The black-hole source Cyg X-1 in the low/hard state is well described by our model.
Key words: accretion, accretion disks / black hole physics / radiation mechanisms: non-thermal / methods: statistical / X-rays: stars
© ESO, 2003
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.