Magnetic pressure support and accretion disk spectra

被引:47
作者
Blaes, Omer M. [1 ]
Davis, Shane W.
Hirose, Shigenobu
Krolik, Julian H.
Stone, James M.
机构
[1] Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA
[2] JAMSTEC, Earth Simulator Ctr, Kanazawa Ku, Yokohama, Kanagawa 2360001, Japan
[3] Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA
[4] Princeton Univ, Dept Astrophys Sci, Princeton, NJ 08544 USA
关键词
accretion; accretion disks; MHD; radiative transfer; X-rays : binaries;
D O I
10.1086/503741
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
Stellar atmosphere models of ionized accretion disks have generally neglected the contribution of magnetic fields to the vertical hydrostatic support, although magnetic fields are widely believed to play a critical role in the transport of angular momentum. Simulations of magnetorotational turbulence in a vertically stratified shearing box geometry show that magnetic pressure support can be dominant in the upper layers of the disk. We present calculations of accretion disk spectra that incorporate vertical magnetic pressure and dissipation profiles derived from the radiation magnetohydrodynamical simulation of Hirose, Krolik, & Stone. Magnetic pressure support generically produces a more vertically extended disk atmosphere with a larger density scale height. This acts to harden the spectrumcompared to models that neglect magnetic pressure support. We estimate the significance of this effect on disk-integrated spectra by calculating an illustrative disk model for a stellar mass black hole, assuming that similar magnetic pressure support exists at all radii.
引用
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页码:1402 / 1407
页数:6
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