TeV Afterglows of Gamma-Ray Bursts: Theoretical Analysis and Prospects for Future Observations

TL;DR

This paper models TeV gamma-ray burst afterglows using a relativistic fireball framework, revealing diverse physical processes and emphasizing the importance of late-time observations for understanding particle acceleration.

Contribution

It provides a detailed theoretical analysis of TeV GRB afterglows, constraining model parameters and highlighting the significance of late-time multi-energy observations.

Findings

Different TeV GRBs show varied maximum particle energies.

Late afterglow emissions depend on particle acceleration limits.

Future TeV observations can diagnose GRB physical processes.

Abstract

Recent detections of gamma-ray bursts (GRBs) at TeV energies opened new prospects for investigating radiative environments and particle acceleration mechanisms under extreme conditions. In this paper, we study the afterglows of these GRBs - namely GRB 180720B, GRB 190114C, GRB 190829A, GRB 201216C, and GRB 221009A - modeling their synchrotron and inverse Compton emission within the framework of an optimized relativistic fireball model. We constrain the model parameters and their temporal evolution by applying our theoretical model to the high-energy emission in the X-ray and GeV-TeV energy bands observed at intermediate and late times. Our results reveal interesting differences among the TeV-detected GRBs, potentially reflecting a variety of underlying physical processes that lead to different maximum energies $E_{\text{max}}= \, \gamma_{\text{max}}\, m_e \, c^2$ of the accelerated particles responsible for the GRB high-energy emission. We indeed obtain different behaviors of the late TeV afterglows that ultimately depend on $\gamma_{\text{max}}$. We discuss how late afterglow observations - on timescales of hours and days - of X-ray and GeV-TeV emissions are crucial for providing diagnostics of the physical processes behind GRBs, and we emphasize the theoretical expectations for future TeV observations.