GLAST and Lorentz violation

Abstract

We study possible Lorentz violations by means of gamma ray bursts with special focus onthe large array telescope of GLAST (gamma ray large area space telescope),where we concentrate on models with linear corrections to the speed of light. Wesimulate bursts with gtobssim and introduce a Lorentz violating term in the arrivaltimes of the photons. We further perturb these arrival times and energies with aGaussian distribution corresponding to the time and energy resolution of GLAST. Wethen vary the photon flux in gtobssim in order to derive a relation between thephoton number and the standard deviation of the Lorentz violating term. Weconclude with the fact that our maximum likelihood method as first developed inLamon et al (2008 Gen. Rel. Grav. 40 1731 [0706.4039] [gr-qc]) is able to make astatement on whether Nature breaks the Lorentz symmetry if the number ofbursts with known redshifts is of the order of 100. However, the systematic errorscaused by unknown mechanisms for photon emission are not considered here,despite the fact that these errors should be the main obstacle to detecting Lorentzviolations.