THE DURATION PHOTON ENERGY RELATION OF GAMMA-RAY BURSTS AND ITS INTERPRETATIONS

Fenimore et al. have recently presented a very tight correlation betwe en the spectral and the temporal structure in gamma-ray bursts (GRBs). In particular, they discovered that the durations of the constituent subpulses which make up the time profile of a given GRB have a well-de fined power-law dependence of index similar or equal to 0.45 on the en ergy E of the observed photons. In this paper we present two simple mo dels which can account in a straightforward fashion for the observed c orrelation. These models involve (1) the impulsive injection of a popu lation of relativistic electrons and their subsequent cooling by synch rotron radiation, and (2) The impulsive injection of monoenergetic hig h-energy photons in a medium of Thompson depth tau(T) similar to 5 and their subsequent downgrading in energy due to electron scattering. We present arguments for distinguishing between these two models from th e existing data.