A classical gamma-ray burst repeater, GBS 0855-00?

We find in the sample of gamma-ray bursts, observed by the BATSE experiment on the Compton Gamma Ray Observatory, a conspicuous set of bursts, GB 910430, GB 910501, GB 910502, GB 910722, and GB 910725, which are clustered in both space and time, separated in position by less than their positional uncertainty and separated in time by less than a few days. From a statistical analysis of the clustering, we find that these five burst positions are consistent with a single common source at the 85 percent confidence level, while we estimate that the probability of such a cluster of five bursts being random is less than 0.0002. Thus, we suggest that these bursts arise from a repeating source at a location of about 0855-00. Unlike most of the 'soft' gamma-ray repeaters, these repeating bursts have relatively hard spectra, and widely varying durations and light curves, that are indistinguishable from the common 'classical' gamma-ray bursts.