Multiwavelength constraints on gamma-ray burst sources

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1989

OSTI ID:6864322

Hartmann, D H.B.

Cosmic {gamma}-ray bursts remain a puzzle since their discovery about two decades ago. No quiescent counterpart of a {gamma}-ray burst source has been unambiguously identified in any wavelength band and the angular distribution of sources in the sky is isotropic and indicates no association with any galactic or extragalactic features, thus leaving the burster distance scale undetermined. There is observational evidence that {gamma}-ray bursts are associated with neutron stars in the general vicinity of the galaxy. Lacking unambiguous counterpart identification at low energies, the author attempts to determine the burster distance scale using statistical tools. The angular and brightness distribution of {gamma}-ray bursts are analyzed. Quantitative estimates of the large-scale isotropy and small-scale angular clustering are used to constrain current detector sampling depths for extragalactic models and local models involving neutron stars. The distribution of neutron stars is calculated by using a realistic model of the mass distribution in the Galaxy and integrating stellar orbits using initial conditions obtained from radio observations of pulsars. Based on the statistical analysis it is concluded that {gamma}-ray burst sources are either very near (kpc scale) or very far (100 Mpc scale). Statistical analysis of data expected from the Gamma Ray Observatory could produce evidence in favor of a galactic origin of {gamma}-ray bursts, but that cannot replace optical identification of a {gamma}-ray burst counterpart. At low energies, counterparts may be detected in quiescence or by low energy (optical-UV) emission simultaneous with the {gamma}-ray outburst. Evidence exists that {gamma}-ray bursts might be accompanied by optical emission.

• Research Organization: California Univ., Santa Cruz, CA (USA)
• OSTI ID: 6864322
• Country of Publication: United States
• Language: English

Related Subjects

640101* -- Astrophysics & Cosmology-- Cosmic Radiation
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BRIGHTNESS
COSMIC GAMMA BURSTS
COSMIC GAMMA SOURCES
COSMIC RADIATION
COSMIC RAY SOURCES
DETECTION
DISTANCE
DISTRIBUTION
GALAXIES
IONIZING RADIATIONS
MATHEMATICAL MODELS
MATHEMATICS
MILKY WAY
NEUTRON STARS
OPTICAL PROPERTIES
ORIGIN
PHYSICAL PROPERTIES
PRIMARY COSMIC RADIATION
RADIATIONS
SPATIAL DISTRIBUTION
STARS
STATISTICS