TIME DILATION OF BATSE GAMMA-RAY BURSTS

We perform several nonparametric correlation tests on the BATSE 3B dat a to search for evidence of cosmological time dilation. These tests ac count for the effects of data truncation due to threshold effects in b oth limiting brightness and limiting duration, enabling us to utilize a larger number of bursts than in previous analyses. We find little si gnificant evidence for correlation between various measures of peak in tensity and duration, but the tests cannot conclusively rule out time dilation factors of 2 or less without more data. There is stronger evi dence for a positive correlation between fluence and duration, which i f confirmed would rule out simple no-evolution cosmological models unl ess there is a strong intrinsic correlation between the total radiant energy and the duration of bursts.