Spectral classification and variation of Fermi GRBs

The Fermi GBM catalog contains general physical quantities of the observed objects and also estimated parameters (peak energy, spectral indices, intensity) from four fitted spectral models (Band, smoothly broken power law, Comptonized, power law) for the peak flux and the fluence. We studied the nature of the errors of the peak flux, the fluence, and duration parameters. We have found a linear correlation between the logarithm of the measured quantities and their error bars. We interpret our results as an indication that the peak flux, fluence and duration follow a Poissonic distribution.