On the Shape of Pulse Spectra in Gamma‐Ray Bursts
- 20 February 1999
- journal article
- Published by American Astronomical Society in The Astrophysical Journal
- Vol. 512 (2), 693-698
- https://doi.org/10.1086/306818
Abstract
The discovery (Liang & Kargatis 1996), that the peak energy of time-resolved spectra of gamma-ray burst (GRB) pulses decays exponentially with fluence, is analytically shown to imply that the time-integrated photon number spectrum of a pulse should have a unique shape, given by an underlying E^-1 behavior. We also show that the asymptotic low energy normalization of the time-integrated spectrum is equal to the exponential decay constant. We study analytically how this general behavior is modified in more realistic situations and show that diversity is then introduced in the properties of time-integrated GRB pulse spectra. We argue that further diversity will occur in time-integrated multi-pulse (complex) GRB spectra. The total energy received per cm^2 is approximately the decay constant times the maximum peak energy of the pulse. Our analytical results connect the properties of the time-integrated pulse spectrum with those of the time-resolved spectra, and can thus be used when studying observed GRB pulse spectra. We illustrate with the bright burst GRB 910807 and comment on GRB 910525 and GRB 921207.Keywords
This publication has 8 references indexed in Scilit:
- BATSE Observations of Gamma‐Ray Burst Spectra. IV. Time‐resolved High‐Energy SpectroscopyThe Astrophysical Journal, 1998
- Evolution of the Low-Energy Photon Spectra in Gamma-Ray BurstsThe Astrophysical Journal, 1997
- BATSE Observations of Gamma‐Ray Burst Spectra. III. Low‐Energy Behavior of Time‐averaged SpectraThe Astrophysical Journal, 1996
- The Third BATSE Gamma-Ray Burst CatalogThe Astrophysical Journal Supplement Series, 1996
- Dependence of the spectral evolution of γ-ray bursts on their photon fluenceNature, 1996
- BATSE observations of gamma-ray burst spectra. 2: Peak energy evolution in bright, long burstsThe Astrophysical Journal, 1995
- The continuum spectral characteristics of gamma-ray bursts observed by BATSEThe Astrophysical Journal, 1994
- BATSE observations of gamma-ray burst spectra. I - Spectral diversityThe Astrophysical Journal, 1993