Spectral Lag Transition of 32 Fermi Gamma-ray Bursts and their Application on Constraining Lorentz Invariance Violation

TL;DR

This study analyzes spectral lag transitions in 32 Fermi GRBs to set physical limits on Lorentz Invariance Violation, constraining quantum gravity energy scales through empirical data fitting.

Contribution

It systematically examines GRB spectral lag transitions and applies LIV effects to constrain quantum gravity energy scales, providing new limits based on a comprehensive sample.

Findings

Lag transition occurs around 400 keV in GRBs.

Lower limit of linear $E_{QG}$ is about 1.5×10^{14} GeV.

Lower limit of quadratic $E_{QG}$ is about 8×10^{5} GeV.

Abstract

The positive-to-negative transition of spectral lag is an uncommon feature reported in a small number of GRBs. An application of such a feature has been made to constrain the critical quantum gravity energy ($E_{\rm QG}$) of the light photons under the hypothesis that the Lorentz invariance might be violated. Motivated by previous case studies, this paper systematically examined the up-to-date Fermi/GBM GRB sample for the lag transition feature to establish a comprehensive physical limit on the Lorentz Invariance Violation (LIV). This search resulted in 32 GRBs with redshift available, which exhibit the lag-transition phenomenon. We first fit each of the lag-E relations of the 32 GRBs with an empirical smoothly broken power law function, and found that the lag transition occurs typically at about 400 keV. We then implemented the LIV effect into the fit, which enabled us to constrain the lower limit of the linear and quadratic values of $E_{\rm QG}$, which are typically distributed at $1.5\times 10^{14}$ GeV and $8\times 10^{5}$ GeV, respectively.