Spectral Properties of Short Gamma‐Ray Bursts

It is well known that short GRBs have harder spectra than long GRBs, but the spectral differences between these two modes of the duration distribution have not been examined in detail. Using a database of standard model fits to GRBs in the BATSE 4B catalog, we compare the distributions of spectral parameters of short and long bursts. We also investigate the duration dependence of the same parameters within each mode. We find a consistent pattern of duration dependence: the mean values of all parameters differ significantly between the two duration classes, with short bursts being consistently harder. However, the same parameters show only weak dependence on duration within each class. We discuss the implications of these results for our understanding of GRBs.