Search for Gamma Ray Bursts with the ARGO-YBJ Detector in Shower Mode

TL;DR

This study used the ARGO-YBJ detector to search for gamma ray emissions from 156 GRBs in the 10-1000 GeV range, finding no significant signals but setting upper limits on their energy fluence.

Contribution

First search for gamma ray emissions from satellite-triggered GRBs using the ARGO-YBJ detector in shower mode, establishing upper limits in the GeV energy range.

Findings

No significant gamma ray excess detected coincident with GRBs.

Upper limits on energy fluence range from 10^-5 to 10^-1 erg/cm^2.

Constraints on high-energy emission models for GRBs.

Abstract

The ARGO-YBJ detector, located at the Yangbajing Cosmic Ray Laboratory (4300 m a. s. l., Tibet, China), was a full coverage air shower array dedicated to gamma ray astronomy and cosmic ray studies. The wide field of view (~ 2 sr) and high duty cycle (> 86%), made ARGO-YBJ suitable to search for short and unexpected gamma ray emissions like gamma ray bursts (GRBs). Between 2007 November 6 and 2013 February 7, 156 satellite-triggered GRBs (24 of them with known redshift) occurred within the ARGO-YBJ field of view. A search for possible emission associated to these GRBs has been made in the two energy ranges 10-100 GeV and 10-1000 GeV. No significant excess has been found in time coincidence with the satellite detections nor in a time window of one hour after the bursts. Taking into account the EBL absorption, upper limits to the energy fluence at 99% of confidence level have been evaluated,with values ranging from ~ 10-5 erg cm-2 to ~10-1 erg cm-2.