New stringent LIV limits from astrophysical gamma-ray sources

Abstract

Lorentz invariance violation (LIV) introduced as a generic modification to particle dispersion relation can change the photon energy threshold of pair-production, which modifies the extragalactic background light (EBL) absorption of gamma rays from astrophysical sources. In this note, we report an innovative data analysis that allows us to extract unprecedented information from the most updated data set composed of 111 energy spectra of 38 different sources measured by current gamma-ray observatories. The outcome technique and results maximize the chances to find or discriminate LIV signals in any future search and reduce the biases in current analyses. Therefore, we report stringent limits for the LIV energy scale at first and second leading order in high energy gamma-rays. These limits are better than the ones current available in the literature for subluminal searches of LIV, irrespectively of many tested uncertainties, such as, poor knowledge of the EBL, large uncertainties in the intrinsic energy spectra functional form, energy resolution, selection of spectra and the energy bins selection used in the calculation of the intrinsic energy spectra.