High-energy emission from GRBs: 10 years with Fermi-LAT

TL;DR

This paper presents a comprehensive 10-year analysis of high-energy gamma-ray emissions from GRBs detected by Fermi-LAT and other instruments, significantly expanding the known sample and providing new insights into their properties.

Contribution

It introduces a systematic search that doubles the detection efficiency, identifying 186 high-energy GRBs and analyzing their temporal, spectral, and energetic characteristics with unprecedented sensitivity.

Findings

Detected 186 high-energy GRBs over 10 years, more than five times previous catalog.

Analyzed the temporal and spectral properties of the high-energy emission.

Provided insights into the potential for very high-energy emission from GRBs.

Abstract

In 2018, the Fermi mission celebrated its first decade of operation. In this time, the Large Area Telescope (LAT) has been very successful in detecting the high-energy emission (>100 MeV) from Gamma-Ray Bursts (GRBs). The analysis of particularly remarkable events - such as GRB 080916C, GRB 090510 and GRB 130427A - has been presented in dedicated publications. Here we present the results of a new systematic search for high-energy emission from the full sample of GRBs detected in 10 years by the Fermi Gamma-Ray Burst Monitor, as well as Swift, AGILE, Integral and IPN bursts, featuring a detection efficiency more than 50\%\ better than previous works, and returning 186 detections during 10 years of LAT observations. This milestone marks a vast improvement from the 35 events contained in the first LAT GRB catalog (covering the first 3 years of Fermi operations). We assess the characteristics of the GRB population at high energy with unprecedented sensitivity, covering aspects such as temporal properties, energetics and spectral index of the high-energy emission. Finally, we show how the LAT observations can be used to inform theory, in particular the prospects for very high-energy emission.