Detection of afterglow emission up to 100 GeV through a stacking analysis of gamma-ray bursts

Fuente: arXiv
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Main Authors: Chen, Shi, Yuan, Qiang, Guo, Yi-Qing, Dai, Ben-Zhong, Gao, He, Zhang, Bing
Format: Preprint
Published: 2026
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author Chen, Shi
Yuan, Qiang
Guo, Yi-Qing
Dai, Ben-Zhong
Gao, He
Zhang, Bing
author_facet Chen, Shi
Yuan, Qiang
Guo, Yi-Qing
Dai, Ben-Zhong
Gao, He
Zhang, Bing
contents High-energy gamma-ray (>GeV) emission of gamma-ray bursts (GRBs) is very important in probing the jet evolution and particle acceleration of GRBs. The observations of high-energy photons are limited except for a few very bright GRBs, hindering precise measurements of the spectral and temporal evolutions of GRBs. Here we report the detection of high-energy gamma-ray emission up to 100 GeV with Fermi-LAT using a stacking analysis of a collection of 330 GRBs. High significance detection of the emission has been found, and the precise light curves and energy spectra can be measured. The light curves and time-resolved spectra of the sub-sample of 220 LAT individually detected GRBs can be well explained by the standard afterglow emission from a population of GRBs with both synchrotron and synchrotron self-Compton mechanisms, assuming a distribution of initial Lorentz factors. However, the emission of the relatively weak sample of the 110 LAT individually undetected GRBs cannot be well reproduced in the same framework, indicating the existence of possible energy injection effect in the GeV band for the first time. The observations hence provide new insights in understanding the high-energy emission of GRBs.
format Preprint
id arxiv_https___arxiv_org_abs_2603_09179
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Detection of afterglow emission up to 100 GeV through a stacking analysis of gamma-ray bursts
Chen, Shi
Yuan, Qiang
Guo, Yi-Qing
Dai, Ben-Zhong
Gao, He
Zhang, Bing
High Energy Astrophysical Phenomena
High-energy gamma-ray (>GeV) emission of gamma-ray bursts (GRBs) is very important in probing the jet evolution and particle acceleration of GRBs. The observations of high-energy photons are limited except for a few very bright GRBs, hindering precise measurements of the spectral and temporal evolutions of GRBs. Here we report the detection of high-energy gamma-ray emission up to 100 GeV with Fermi-LAT using a stacking analysis of a collection of 330 GRBs. High significance detection of the emission has been found, and the precise light curves and energy spectra can be measured. The light curves and time-resolved spectra of the sub-sample of 220 LAT individually detected GRBs can be well explained by the standard afterglow emission from a population of GRBs with both synchrotron and synchrotron self-Compton mechanisms, assuming a distribution of initial Lorentz factors. However, the emission of the relatively weak sample of the 110 LAT individually undetected GRBs cannot be well reproduced in the same framework, indicating the existence of possible energy injection effect in the GeV band for the first time. The observations hence provide new insights in understanding the high-energy emission of GRBs.
title Detection of afterglow emission up to 100 GeV through a stacking analysis of gamma-ray bursts
topic High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2603.09179