GLAST, GRBs, and Quantum Gravity

TL;DR

This paper evaluates GLAST's potential to detect quantum gravity effects by analyzing gamma-ray burst data, predicting that GLAST can observe energy-dependent photon dispersion if such effects exist.

Contribution

The study calibrates GLAST's sensitivity to quantum gravity-induced photon dispersion using simulations of GRB observations, highlighting its capability to test QG theories.

Findings

GLAST expected to detect over 200 GRBs annually.

Sensitivity to energy-dependent dispersion of a few tens of GeV.

Potential to observe QG effects within 1-2 years of data collection.

Abstract

The fast temporal structures and cosmological distances of gamma-ray bursts (GRBs) afford a natural laboratory for testing theories of frequency-dependent propagation of high-energy photons, as predicted for quantum gravity (QG). We calibrate the sensitivity of the proposed Gamma-ray Large Area Space Telescope (GLAST) by performing simulations which include: the response of GLAST to a GRB fluence distribution; a distribution of spectral power-law indices similar to the EGRET sample; and consideration of gamma-gamma attenuation, significant above ~ 10 GeV for redshifts z > 3 - 5. We find that GLAST should detect > 200 GRBs per year, with sensitivity to a few tens of GeV for a few bursts. GLAST could detect the energy- and distance-dependent dispersion (10 ms / GeV / Gpc) predicted by QG with 1 - 2 years of observations. Attribution to QG would require correlation of GRB redshifts with the temporal and energetic signatures.