Study of the Temporal and Spectral Characteristics of gamma Ray Bursts.

摘要

Gamma-ray burst data obtained from the ISEE-3Gamma Ray Burst Spectrometer and the Solar Maximum Mission's Hard X-ray Burst Spectrometer (HXRBS) were analyzed to yield information on burst temporal and spectral characteristics. A Monte Carlo approach was used to simulate the HXRBS response to candidate spectral models. At energies above about 100keV,the spectra are well fit by exponential forms. At lower energies, 30keV to 60keV,depressions below the model continua are apparent in some bursts. The depressions are not instrumental or data-reduction artifacts. The event selection criterion of the ISEE-3experiment is based on the time to accumulate a present number of photons rather than the photon count per unit time and is consequently independent of event duration for a given burst intensity,unlike most conventional systems. As a result, a significantly greater percentage of fast,narrow events have been detected. The ratio of count rates from two ISEE-3detectors indicates that bursts with durations or aprox. one second have much softer spectra than longer bursts.