Correlated optical and gamma emissions from GRB 081126

TL;DR

This paper reports the first well-resolved observation of a time lag between optical and gamma-ray emissions in GRB 081126, offering insights into gamma-ray burst models and potential tests of quantum gravity theories.

Contribution

It presents the first detailed measurement of a time lag between optical and gamma-ray emissions during a GRB's prompt phase, combining multi-instrument data.

Findings

Optical emission lags gamma-ray pulse by 8.4 seconds.

Optical and gamma-ray emissions are correlated with a measurable time delay.

Results provide constraints on GRB emission models and quantum gravity theories.

Abstract

We present an analysis of time-resolved optical emissions observed from the gamma-ray burst GRB 081126 during the prompt phase. The analysis employed time-resolved photometry using optical data obtained by the TAROT telescope, using BAT data from the Swift spacecraft, and time-resolved spectroscopy at high energies from the GBM instrument onboard the Fermi spacecraft. The optical emission of GRB 081126 is found to be compatible with the second gamma emission pulse shifted by a positive time lag of 8.4 $\pm$ 3.9 s. This is the first well-resolved observation of a time lag between optical and gamma emissions during a gamma-ray burst. Our observations could potentially provide new constraints on the fireball model for gamma-ray burst early emissions. Furthermore, observations of time lags between optical and gamma ray photons provides an exciting opportunity to constrain quantum gravity theories.