The Hurst exponent of Fermi gamma-ray bursts

Using a wavelet decomposition technique, we have extracted the Hurst exponent for a sample of 46 long and 22 short gamma-ray bursts (GRBs) detected by the Gamma-ray Burst Monitor aboard the Fermi satellite. This exponent is a scaling parameter that provides a measure of long-range behaviour in a time series. The mean Hurst exponent for the short GRBs is significantly smaller than that for the long GRBs. The separation may serve as an unbiased criterion for distinguishing short and long GRBs.