Study of Quantum Gravity Effects in INTEGRAL Gamma-Ray Bursts

Aims. We search for possible time lags caused by quantum gravitational (QG) effects using gamma-ray bursts detected by INTEGRAL. The advantage of this satellite is that we have at our disposal the energy and arrival time of every single photon, which enhances the precision of the time resolution. Methods. We present a new method for seeking time lags in unbinned data using a maximum likelihood. We also support our conclusions with Monte Carlo simulations. Results. The Monte Carlo simulations show that today’s satellites are not apt to measure effects at the order of the Planck mass. However, a naive analysis of the data shows a mass scale well below the expected one. Only by correcting for internal time lags are we able to give a lower bound on the quantum gravitation mass scale that is in accordance with predictions. Conclusions. A possible detection of quantum gravitational effects can only be achieved by using satellites that can detect more energetic photons, as the Gamma-ray Large Area Space Telescope (GLAST) will be able to do. Furthermore, we disagree with previous studies in which a non-monotonic function of the redshift was used to perform a linear fit.