Lorentz violation from cosmological objects with very high energy photon emissions

TL;DR

This paper investigates potential Lorentz violation effects predicted by quantum gravity theories by analyzing very high energy photon emissions from distant cosmological sources, providing constraints on quantum gravity energy scales.

Contribution

It presents the first robust analysis of VHE gamma-ray bursts considering intrinsic source time lags and estimates quantum gravity energy scales for linear and quadratic energy dependence.

Findings

Estimated quantum gravity energy scale ~2 x 10^{17} GeV (linear dependence)

Estimated quantum gravity energy scale ~5 x 10^9 GeV (quadratic dependence)

Limited data prevents stronger constraints, highlighting need for further observations.

Abstract

Lorentz violation (LV) is predicted by some quantum gravity theories, where photon dispersion relation is modified, and the speed of light becomes energy-dependent. Consequently, it results in a tiny time delay between high energy photons and low energy ones. Very high energy (VHE) photon emissions from cosmological distance can amplify these tiny LV effects into observable quantities. Here we analyze four VHE $\gamma$-ray bursts (GRBs) from Fermi observations, and briefly review the constraints from three TeV flares of active galactic nuclei (AGNs) as well. One step further, we present a first robust analysis of VHE GRBs taking the intrinsic time lag caused by sources into account, and give an estimate to quantum gravity energy $\sim 2 \times 10^{17}$ GeV for linear energy dependence, and $\sim 5 \times 10^9$ GeV for quadratic dependence. However, the statistics is not sufficient due to the lack of data, and further observational results are desired to constrain LV effects better.