| Abstract: | GRBs can be profitably used to probe both galaxy evolution at high-z and fundamental physics, such as breaking or deforming Lorentz Invariance near the Planck scale (E_Plank=M_Plank c^2= 1.22 10^{19} GeV). A key test of Lorentz invariance is a light travel time effect, the possible variation of photon speed with energy. A small variation in photon speed, when accumulated over cosmological light-travel times, may be revealed by observing characteristic features in the GRBs lightcurves at high energy. In this talk I consider all the GRBs detected by the Large Area Telescope (LAT) on board of the Fermi Gamma-ray Space Telescope with enough counts to allow a detailed time resolved spectral analysis to provide constraints on the energy scale of the putative Lorentz invariance breaking or deformation E_{QG}. |
