Energy Dependence of Profile Width in Short Gamma-Ray Bursts

Using the high time-resolution and 64ms resolution data of the burst and transient source experiment, we performed an autocorrelation analysis of the energy dependence of burst pulse width in short gamma-ray bursts. A method free from potential cosmological effects has been proposed. This allows us to use a sample with a size comparable to that used for long and bright bursts. Our result shows that the profiles of short bursts exhibit a very good power-law between profile width and photon energy, with an index ~ -0.3. This result is consistent with a united origin of the bimodal distribution.