Variability Time Scales of GRBs

We have investigated the time variations in the light curves from a sample of long and short Fermi/GBM Gamma ray bursts (GRBs) using an impartial wavelet analysis and compared those results with results from a pulse fitting analysis. We present a direct link between the minimum variability time scales extracted through the wavelet decomposition and the rise times of the shortest pulses extracted via the pulse fits of light curves. The results indicate minimum variabilities from a few milliseconds to several hundred milliseconds are not uncommon.