Intrinsic dependence of gamma-ray burst durations on energy

We have measured T-90 and T-50 as a function of energy for a set of bright BATSE gamma-ray bursts, selected on the basis of their peak photon flux on the 64 ms time scale. These events lie mainly on the -3/2 portion of the log N(> P)-log P curve; thus, in the cosmological scenario their measured characteristics may be relatively free from redshift and time dilation effects, so that the measured dependence of duration on energy may reflect an intrinsic dependence. We examine the compatibility of our results with recent work (1), which showed that the functional dependence of duration on energy is well-represented by a power law.