Precursor active galaxies and the cosmic x-ray background
Technical Report
·
OSTI ID:5305289
It is argued that the cosmic X-ray background (CXB) is not dominated by sources that are usual active galaxies or quasars. A comparable number of objects, young galaxies at z approximately 4 containing massive black holes surrounded by hot optically thin accretion disks, constitute the precursor active galaxies (PAG) postulated here for producing the thermal type spectrum required for the CXB. An evolutionary track for such PAG objects is described which would lead to the active galaxies observed as individual nonthermal sources. Unresolved emission from active galaxies at z 1 could then readily account for most of the nonthermal background observed in the gamma ray band.
- Research Organization:
- National Aeronautics and Space Administration, Greenbelt, MD (USA). Goddard Space Flight Center
- OSTI ID:
- 5305289
- Report Number(s):
- NASA-TM-82087
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
640101* -- Astrophysics & Cosmology-- Cosmic Radiation
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BACKGROUND RADIATION
BLACK HOLES
COSMIC RADIATION
COSMIC RAY SOURCES
COSMIC X-RAY SOURCES
ELECTROMAGNETIC RADIATION
GALAXIES
IONIZING RADIATIONS
RADIATIONS
STAR ACCRETION
STAR EVOLUTION
X RADIATION
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BACKGROUND RADIATION
BLACK HOLES
COSMIC RADIATION
COSMIC RAY SOURCES
COSMIC X-RAY SOURCES
ELECTROMAGNETIC RADIATION
GALAXIES
IONIZING RADIATIONS
RADIATIONS
STAR ACCRETION
STAR EVOLUTION
X RADIATION