| The time profiles of Gamma-Ray Bursts (GRBs) from the Burst and Transient Source Experiment (BATSE) on NASA's Compton Gamma Ray Observatory Satellite show an incredible morphological diversity from single pulse to a long complex sequence of chaotic pulses. We have selected a subset of bursts called FREDs—Fast Rise Exponential Decays—for investigation.; It has already been proposed that “exponential” decay is only an approximation (Schaefer and Dyson, 1996). This work not only confirms that statement, but also finds a bimodality in the histogram of decay rates. Moreover, investigation of the relationship between the decay behavior and some basic characteristics of GRBs shows that the decay rate is independent of burst duration and other GRB characteristics, but is possibly related to the distance by the time dilation effect. |
