Structured coronae of accretion disks

Journal Article · Sun Apr 01 04:00:00 EST 1979 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/156957· OSTI ID:6217494

Galeev, A A; Rosner, R; Vaiana, G S

A model for the fluctuating hard component of intense cosmic X-ray sources (such as Cyg X-1) is developed, based upon the amplification of magnetic fields by convective motions and differential rotation within a hot (T> or approx. =10/sup 6/K) accretion disk. Field reconnection within the inner portion of the disk is shown to be ineffective in limiting field amplification; magnetic fields may therefore attain strengths comparable to the equipartition value, leading to their emergence via buoyancy in the form of looplike structures and resulting in a very hot (T>10/sup 8/K) magnetically confined, structured corona analogous to the observed structure of the solar corona. The energy balance of these loop structures is examined, and it is shown that the disk soft X-ray luminosity determines the predominant energy loss mechanism in loops: at low disk luminosities, thermal bremstrahlung from these loops dominates and contributes a steady, shot-noise--like hard X-ray component. At high disk luminosities the emerging loops are Compton-cooled; the soft X-ray flux from the disk is Comptonized by the emerged loops, forming a transient, flarelike hard X-ray component.

• Research Organization: Harvard-Smithsonian Center for Astrophysics
• OSTI ID: 6217494
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 229:1; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar
Radio & X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ATMOSPHERES
BINARY STARS
CONVECTION
COSMIC RAY SOURCES
COSMIC X-RAY SOURCES
FLUCTUATIONS
FLUID MECHANICS
HYDRODYNAMICS
LUMINOSITY
MAGNETIC FIELD CONFIGURATIONS
MAGNETIC FIELDS
MAGNETOHYDRODYNAMICS
MATHEMATICAL MODELS
MECHANICS
MOTION
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
PLASMA
ROTATION
STAR ACCRETION
STAR EVOLUTION
STAR MODELS
STARS
STELLAR ATMOSPHERES
VARIATIONS