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S. W. Davis, O. M. Blaes (University of California, Santa Barbara), I. Hubeny (University of Arizona)
We present the first self-consistent calculations of non-LTE, relativistic accretion disk models applicable to the high/soft state of black hole X-ray binaries. We include the effects of thermal Comptonization and bound-free and free-free opacities of abundant ion species. Taking into account the relativistic propagation of photons from the local disk surface to an observer at infinity, we present spectra calculated for a variety of accretion rates, black hole spin parameters, disk inclinations, and assumptions of the microphysics of the disk. The last include a variety of viscosity prescriptions and vertical dissipation profiles, including those recently derived from radiation MHD simulations of magnetorotational turbulence.
The computed spectra are remarkably robust and independent of many of the microphysical assumptions. However, the improvement in the physics results in discrepancies with previous, more simplified models, that are easily discernible with modern X-ray observatories. Fitting our spectra with simple, isotropic color-corrected multi-temperature blackbodies results in frequency dependent, 10 percent discrepancies that may affect the fitted parameters of other spectral components, and their interpretation. We compare our models to existing spectral data of the high/soft state, and recover the observed relation between luminosity and inner disk temperature.
We provide an XSPEC table model of our spectral calculations for use by the community.
This work was supported by NASA grant NAG5-13228.
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Bulletin of the American Astronomical Society, 36 #3
© 2004. The American Astronomical Soceity.