Constraining Lorentz invariance violations using the Crab pulsar TeV emission

TL;DR

This study uses gamma-ray data from the Crab pulsar to set limits on Lorentz Invariance Violation, demonstrating pulsars as effective tools for probing quantum gravity effects at high energies.

Contribution

It provides the first constraints on LIV using TeV gamma-ray emission from a pulsar, expanding the astrophysical objects used for such tests beyond AGNs and GRBs.

Findings

No significant energy-dependent time delay observed.

Limits on LIV energy scale are close to current best bounds.

Pulsars are validated as independent LIV probes.

Abstract

Fast variations of gamma-ray flux from Active Galactic Nuclei and Gamma-Ray Bursts can constrain Lorentz Invariance Violation (LIV) because of the delayed (or advanced) arrival of photons with higher energies: this approach has lead to the current world-best limits on the energy scale of Quantum Gravity. Here we report on constraints on LIV studying the gamma-ray emission up to TeV energies from the Galactic Crab pulsar, recently discovered by the MAGIC collaboration. A likelihood analysis of the pulsar events reconstructed for energies above 400 GeV finds no significant variation of energy-dependent arrival time, and 95% CL limits are then obtained on the effective LIV energy scale after taking into account systematic uncertainties. Only a factor of about two less constraining than the current world-best limit on a quadratic LIV scenario, pulsars are now well established as a third and independent class of astrophysical objects suitable to constrain the characteristic energy scale of LIV.