A&A 489, 481-487 (2008)
A jet model for Galactic black-hole X-ray sources: some constraining correlationsN. D. Kylafis1, 2, I. E. Papadakis1, 2, P. Reig2, 1, D. Giannios3, and G. G. Pooley4
1 Physics Department, University of Crete, PO Box 2208, 710 03 Heraklion, Crete, Greece
2 Foundation for Research and Technology-Hellas, PO Box 1527, 711 10 Heraklion, Crete, Greece
3 Max Planck Institute for Astrophysics, Box 1317, 85741 Garching, Germany
4 Astrophysics Group, Cavendish Laboratory, Madingley Road, Cambridge CB3 OHE, UK
Received 28 November 2007 / Accepted 11 July 2008
Context. Some recent observational results impose significant constraints on all the models that have been proposed to explain the Galactic black-hole X-ray sources in the hard state. In particular, it has been found that during the hard state of Cyg X-1 the power-law photon number spectral index, , is correlated with the average time lag, , between hard and soft X-rays. Furthermore, the peak frequencies of the four Lorentzians that fit the observed power spectra are correlated with both and .
Aims. We have investigated whether our jet model can reproduce these correlations.
Methods. We performed Monte Carlo simulations of Compton upscattering of soft, accretion-disk photons in the jet and computed the time lag between hard and soft photons and the power-law index of the resulting photon number spectra.
Results. We demonstrate that our jet model naturally explains the above correlations, with no additional requirements and no additional parameters.
Key words: radiation mechanisms: non-thermal -- accretion, accretion disks -- black hole physics -- methods: statistical -- X-rays: binaries
© ESO 2008