題目：The Crab Nebula, a Self-organized Criticality System?
Several analyses of the Crab Nebula have shown the flux of the low-energy component of the Crab Nebula from synchrotron radiation,
in some short time windows, could be significantly enhanced compared to the average value. In this paper, we investigate the Crab Nebula with
data in about ten years observation of the Fermi-LAT, and we identify 15 significant flares in the gamma-ray light curve of the low-energy component
with 4 days time bin. We confirm these significant flares could be decomposed into a steady synchrotron component, and an involving flare component
with a hard spectral index, about 1.53. We also find an almost linear correlation between the cutoff energy and the energy flux above 100 MeV of the
flare component for each significant outburst. We further decompose the gamma-ray light curve into the quiescent synchrotron and flare components
using a statistical method suitable for the self-organized criticality model. We find the flux of the synchrotron background is consistent with the value
derived from the composite likelihood analysis for significant flares,and a fluence distribution power-law index is about 1.75, which is consistent with
the theoretical prediction of the self-organized criticality system with the spatial dimension S = 3 and indicates that the gamma-ray flares of the Crab
Nebula are possibly driven by the same physical mechanism as that of the solar flares, i.e., magnetic reconnection.