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 repeaters combining data from gamma-ray ex- periments flying on board different satellites and making use of information derived from the bursts detected simultaneously by all the experiments. The proposed method is suitable to corre- late GRB data provided by experiments that overlap partially or totally in time. As an application of this method we have correlated the po- sitions of 57 gamma-ray bursts observed by WATCH/GRANAT and WATCH/EURECA with 1905 bursts detected by BATSE. Comparing the so-called "added correlation" between the WATCH and BATSE bursts with that obtained with simulated WATCH catalogues, we conclude that there 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 repre- sent a population of repeaters in the BATSE sample.