A further study of the BATSE Gamma-Ray Burst duration distribution

Two classes of gamma-ray bursts have been identified so far, characterized by durations shorter and longer than about 2 s. In 1998 two independent papers indicated the existence of the third class of the bursts with duration between approximately 2 and 10 s. In this paper, using the full BATSE Catalog, the maximum likelihood estimation is presented, which gives a 0.5% probability for having only two subclasses. A Monte-Carlo simulation also confirms this probability.