MR. CAMILLE COUTURIER

Some Quantum Gravity (QG) theories allow for a violation of Lorentz invariance (LIV), manifesting as a dependence of the velocity of light in vacuum on its energy. If such a dependence exists, then photons of different energies emitted together by a distant source will arrive at the Earth at different times.High-energy (GeV) transient emissions from distant astrophysical sources such as Gamma-ray Bursts and Active Galaxy Nuclei can be used to search for and constrain LIV. The speaker will detail the analysis techniques applied on data from two leading Gamma-ray telescopes, H.E.S.S. and Fermi-LAT, and present the derived results, which give the best and most robust constraints on the dispersion parameter in vacuum, and on the energy scale at which QG effects causing LIV may arise.