Origin of sub-TeV afterglow emission from gamma-ray bursts GRB 190114C and GRB 180720B

TL;DR

This paper proposes that the sub-TeV afterglow emission in gamma-ray bursts GRB 190114C and GRB 180720B can be explained by a photohadronic process involving high-energy protons interacting with background photons, extending models from blazar studies.

Contribution

It demonstrates for the first time that the photohadronic scenario used for blazar flares is applicable to gamma-ray burst afterglows, providing new insights into their high-energy emission mechanisms.

Findings

Sub-TeV spectra are due to proton-photon interactions in specific regions.

Background photon distributions constrain the bulk Lorentz factors.

Photohadronic processes can explain high-energy gamma-ray emission in GRBs.

Abstract

The detection of GRB 180722B and GRB 190114C in sub-TeV gamma-rays has opened up a new window to study gamma-ray bursts in high energy gamma-rays. Recently it is shown that the synchrotron and inverse Compton processes are responsible for the production of these high energy gamma-rays during the afterglow. Here, for the first time we demonstrate that, the photohadronic scenario which is successful in explaining the multi-TeV flaring in high energy blazars is also applicable for gamma-ray bursts. We show that the sub-TeV spectra of GRB 190114C and GRB 180720B are due to the interaction of high energy protons with the background photons in the synchrotron self-Compton region and synchrotron region respectively. The nature of the background photon distributions help us to constraint their bulk Lorentz factors.