  Discovered more than 50 years ago, gamma-ray burst (GRB) prompt emission
remains the most puzzling aspect of GRB physics. Its complex and irregular
nature should reveal how newborn GRB engines release their energy. In this
respect, the possibility that GRB engines could operate as self-organized
critical (SOC) systems has been put forward. Here, we present the energy,
luminosity, waiting time, and duration distributions of individual pulses of
GRBs with known redshift detected by the Fermi Gamma-ray Burst Monitor (GBM).
This is the first study of this kind in which selection effects are accounted
for. The compatibility of our results with the framework of SOC theory is
discussed. We found evidence for an intrinsic break in the power-law models
that describe the energy and the luminosity distributions.
