MAGNETIC INVERSION AS A MECHANISM FOR THE SPECTRAL TRANSITION OF BLACK HOLE BINARIES

Journal Article · Tue Sep 01 04:00:00 EDT 2009 · Astrophysical Journal (Online)

DOI:https://doi.org/10.1088/0004-637X/702/1/L72; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)· OSTI ID:21333808

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), Journal Name: Astrophysical Journal (Online) Journal Issue: 1 Vol. 702; ISSN 1538-4357
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ACCRETION DISKS
ADVECTION
ANNIHILATION
BLACK HOLES
HARD X RADIATION
MAGNETIC FIELDS
MAGNETOHYDRODYNAMICS
OPTICALLY THICK PLASMA
PERIODICITY
RANDOMNESS
STARS