Thermal pair cloud models of MeV gamma ray emissions from Cygnus X-1 and the Galactic Center

Conference · Tue Sep 12 04:00:00 EDT 1989

OSTI ID:5288531

Liang, E. P.; Dermer, C. D. ^[1]

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1. Lawrence Livermore National Lab., CA (USA)

The HEAO-3 data for the enhanced MeV gamma ray emissions of Cygnus X-1 and the Galactic Center in 1979 can be modeled by thermal emissions from a compact pair-dominated cloud surrounding the black hole. We derive from first principles the structure of such pair clouds and use these results to constrain the mass of the central black hole, the viscosity parameter and other parameters of the innermost accretion flow. We estimate the production and escape of pairs outside the thermal cloud due to collisions of gamma rays with other gamma rays and with x-rays from the disk. The annihilation of such escaped pairs in the cool medium far from the source can lead to detectable narrow 511 keV lines. These results are compared with the variable 511 keV source in the Galactic Center and the upper limits for Cygnus X-1. 12 refs., 2 figs.

• Research Organization: Lawrence Livermore National Lab., CA (USA)
• Sponsoring Organization: DOE/DP
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 5288531
• Report Number(s): UCRL-101948; CONF-900122--4; ON: DE90001169
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar
Radio & X-Ray Sources
640105 -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ACCRETION DISKS
BLACK HOLES
COSMIC GAMMA BURSTS
COSMIC RADIATION
GALAXIES
INTERACTIONS
IONIZING RADIATIONS
PAIR PRODUCTION
PRIMARY COSMIC RADIATION
RADIATIONS
STAR ACCRETION
STAR EVOLUTION
VISCOSITY