Constraining photon dispersion relations from observations of the Vela pulsar with H.E.S.S

TL;DR

This paper uses gamma-ray observations of the Vela pulsar by H.E.S.S. to set new constraints on quantum gravity theories predicting modified photon dispersion relations, leveraging pulsar periodicity data.

Contribution

It introduces a novel method and calibration procedure to constrain quantum gravity effects using pulsar gamma-ray data, providing the first limit with the Vela pulsar.

Findings

First limit on QG energy scale from Vela pulsar data

Method and calibration procedure for analyzing pulsar gamma-ray data

Constraints on Lorentz invariance violation from pulsar observations

Abstract

Some approaches to Quantum Gravity (QG) predict a modification of photon dispersion relations due to a breaking of Lorentz invariance. The effect is expected to affect photons near an effective QG energy scale. This scale has been constrained by observing gamma rays emitted from variable astrophysical sources such as gamma-ray bursts and flaring active galactic nuclei. Pulsars exhibit a periodic emission of possibly ms time scale. In 2014, the H.E.S.S. experiment reported the detection down to 20 GeV of gamma rays from the Vela pulsar having a periodicity of 89 ms. Using a likelihood analysis, calibrated with a dedicated Monte-Carlo procedure, we obtain the first limit on QG energy scale with the Vela pulsar. In this paper, the method and calibration procedure in use will be described and the results will be discussed.