8th HEAD Meeting, 8-11 September, 2004
Session 26 AGN/Galactic Nuclei
Poster, Friday, September 10, 2004, 9:00am-10:00pm

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[26.25] A Monte Carlo Treatment of Radiation Transfer in Black Hole Accretion Disks

C. W. Mauche, D. A. Liedahl (LLNL), M. A. Jimenez-Garate (MIT)

Accreting black holes - in stellar-mass binaries, AGN, and possibly ultraluminous X-ray sources - are one of the most important targets for current and future X-ray observatories. Spectroscopic observations of such systems allow us in principle to determine the mass of the black hole, its spin, and various properties of the accretion disk. However, the detailed models needed to derive these parameters from observations do not exist. To help address this issue, we are developing a Monte Carlo code that calculates the radiation transfer of X-rays impinging on, and emitted by, relativistic black hole accretion disks. The code is designed to be very flexible, allowing us to investigate different source and illumination geometries, and includes at present Compton scattering and bound-free absorption followed by recombination. Even at this early stage of development, we find interesting and important radiation transfer affects, such as conversion of one type of emission feature into others (e.g., Ne X Lyman alpha photons reprocessed into C V-VI, N VI-VII, and O VII-VIII recombination lines and continuua). We give an overview of our Monte Carlo code, some of the results derived to date, and plans for future improvements, including line opacity and gravitational light bending.

This work was performed under the auspices of the US Department of Energy by University of California, Lawrence Livermore National Laboratory under contract W-7405-Eng-48.


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