A simple method to test for energy-dependent dispersion in high energy light curves of astrophysical sources

We present a method of testing for the presence of energy dependent dispersion in transient features of a light curve. It is based on minimising the Kolmogorov distance between two cumulative event distribution functions. The unbinned and non-parametric nature of the test makes it particularly suitable for searches of statistically limited data sets and we also show that it performs well in the presence of modest energy resolutions typical of gamma-ray observations (∼20%). We illustrate its potential to set constraints on quantum-gravity induced Lorentz invariance violation effects from observations by the current and future generation of ground-based gamma-ray telescopes.