Electron-positron processes and spectral evolution in black hole accretion disk dynamo models for AGN sources of the cosmic X-ray and. gamma. ray backgrounds

Conference · Sat Jan 01 04:00:00 EST 1983 · AIP Conf. Proc.; (United States)

OSTI ID:6049415

Leiter, D

This work discusses a black hole accretion disk dynamo model for Active Galactic Nuclei (AGN) sources of the cosmic X-ray and ..gamma.. ray backgrounds which involves both thermal and nonthermal accretion disk processes around greater than or equal to 10/sup 8/M/sub sun/ Kerr black holes. Before black hole spin-up to the Kerr metric state, the large value of the compactness parameter L(luminosity)/r(size of emitting region) > 10/sup 30/erg/cm-sec associated with the L/L/sub Edd/ less than or equal to l luminosity ratio in Precursor Active Galaxies (PAG) suppresses all nonthermal emission mechanisms. In this PAG state the resulting emission is predominantly thermal and is due to Comptonization of soft photons by an electron-positron plasma, generated within the hot accretion disk region by ..gamma.. + ..gamma.. reversible e+/- processes in the transrelativistic regime. While the underlying plasma in the PAG accretion disk hot inner region may be optically thin initially, the overall effect of the copious ..gamma.. + ..gamma.. reversible e+/- generated electron-positron plasma is to push the overall optical depth to tau greater than or equal to 1. This has two main effects: a) it causes the resulting Comptonized spectrum of X-radiation from PAG to be associated with a flat spectral index comparable to that of the residual Cosmic X-ray Background (CXB), and b) the copious ..gamma.. + ..gamma.. reversible e+/- within the hot accretion disk region play the role of a phase transition thermostat, and act to maintain the temperature of the hot inner region at greater than or equal to 109/sup 0/K. 16 references.

• Research Organization: NASA Goddard Space Flight Center, Greenbelt, MD
• OSTI ID: 6049415
• Report Number(s): CONF-830136-
• Conference Information: Journal Name: AIP Conf. Proc.; (United States) Journal Volume: 101
• Country of Publication: United States
• Language: English

Related Subjects

640103* -- Astrophysics & Cosmology-- Quasi-Stellar
Radio
& X-Ray Sources-- (-1987)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ACCRETION DISKS
BLACK HOLES
COSMIC GAMMA SOURCES
COSMIC RAY SOURCES
COSMIC X-RAY SOURCES
ELECTRON PAIRS
GALACTIC EVOLUTION
GALAXY NUCLEI
KERR METRIC
LUMINOSITY
MATHEMATICAL MODELS
METRICS
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
PLASMA