On external shock model to explain the high-energy emission: GRB 940217, GRB 941017 and GRB 970217A

TL;DR

This paper proposes a leptonic external shock model to explain the high-energy emission in three specific gamma-ray bursts, highlighting a two-component emission process involving synchrotron self-Compton from reverse and forward shocks.

Contribution

It introduces a novel leptonic external shock model that accounts for both prompt and extended high-energy emission phases in GRBs 940217, 941017, and 970217A.

Findings

Model successfully reproduces observed fluxes and break energies.

Two emission components correspond to reverse and forward shocks.

Extended GeV emission lasts hundreds of seconds after the burst.

Abstract

We present a leptonic model on the external shock context to describe the high-energy emission of GRB 940217, GRB 941017 and GRB 970217A. We argue that the emission consists of two components, one with a similar duration of the burst, and a second, longer-lasting GeV phase lasting hundred of seconds after the prompt phase. Both components can be described as synchrotron self-Compton emission from a reverse and forward shock respectively. For the reverse shock, we analyze the synchrotron self-Compton in the thick-shell case. The calculated fluxes and break energies are all consistent with the observed values.