A BATSE-BASED SEARCH FOR REPEATERS IN THE SAMPLE OF GAMMA-RAY BURSTS DETECTED BY THE WATCH EXPERIMENT

This study is the first known attempt to search for gamma-ray burst re peaters combining data from gamma-ray experiments flying on board diff erent satellites and making use of information derived from the bursts detected simultaneously by all the experiments. The proposed method i s suitable to correlate GRB data provided by experiments that overlap partially or totally in time. As an application of this method we have correlated the positions of 57 gamma-ray bursts observed by WATCH/GRA NAT and WATCH/EURECA with 1905 bursts detected by BATSE. Comparing the so-called ''added correlation'' between the WATCH and BATSE bursts wi th that obtained with simulated WATCH catalogues, we conclude that the re is no indication of recurrent activity of WATCH bursts in the BATSE sample. We derive an upper limit of 15.8%, with a confidence level of 94%, for the number of WATCH gamma-ray bursts that could represent a population of repeaters in the BATSE sample.