MAGNETIC INVERSION AS A MECHANISM FOR THE SPECTRAL TRANSITION OF BLACK HOLE BINARIES
- Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, NY 14623 (United States), E-mail: iigu@lle.rochester.edu
A mechanism for the transition between low/hard, high/soft, and steep power law (SPL) spectral states in black hole X-ray binaries is proposed. The low/hard state is explained by the development of a magnetically arrested accretion disk attributable to the accumulation of a vertical magnetic field in a central bundle. This disk forms powerful jets and consists of thin spiral accretion streams of a dense optically thick plasma surrounded by a hot, magnetized, optically thin corona, which emits most of the energy in hard X-rays. State transition occurs because of the quasi-periodic or random inversion of poloidal magnetic fields in the accretion flow supplied by the secondary star. The inward advection of the inverted field results in a temporal disappearance of the central bundle caused by the annihilation of the opposed fields and restoration of the optically thick disk in the innermost region. This disk represents the high/soft state. The SPL state develops at the period of intensive field annihilation and precedes the high/soft state. The continuous supply of the inverted field leads to a new low/hard state because of the formation of another magnetically arrested disk.
- OSTI ID:
- 21333808
- Journal Information:
- Astrophysical Journal (Online), Vol. 702, Issue 1; Other Information: DOI: 10.1088/0004-637X/702/1/L72; Country of input: International Atomic Energy Agency (IAEA); ISSN 1538-4357
- Country of Publication:
- United States
- Language:
- English
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