Exploring Anisotropic Lorentz Invariance Violation from the Spectral-Lag Transitions of Gamma-Ray Bursts

TL;DR

This study analyzes spectral-lag transitions in 32 gamma-ray bursts to constrain anisotropic Lorentz invariance violation, accounting for intrinsic source effects and providing complementary bounds to existing constraints.

Contribution

It introduces a systematic method to test Lorentz-violating effects using spectral-lag transition features in GRBs, considering intrinsic time lags.

Findings

Constraints on Lorentz-violating coefficients with mass dimension d=6 and 8.

Spectral-lag transition features can provide robust bounds on Lorentz violation.

Results complement existing bounds but are not the most restrictive.

Abstract

The observed spectral lags of gamma-ray bursts (GRBs) have been widely used to explore possible violations of Lorentz invariance. However, these studies were generally performed by concentrating on the rough time lag of a single highest-energy photon and ignoring the intrinsic time lag at the source. A new way to test nonbirefringent Lorentz-violating effects has been proposed by analyzing the multi-photon spectral-lag behavior of a GRB that displays a positive-to-negative transition. This method gives both a plausible description of the intrinsic energy-dependent time lag and comparatively robust constraints on Lorentz-violating effects. In this work, we conduct a systematic search for Lorentz-violating photon dispersion from the spectral-lag transition features of 32 GRBs. By fitting the spectral-lag data of these 32 GRBs, we place constraints on a variety of isotropic and anisotropic Lorentz-violating coefficients with mass dimension $d=6$ and $8$. While our dispersion constraints are not competitive with existing bounds, they have the promise to complement the full coefficient space.