GeV Emission during X-Ray Flares from Late Internal Shocks: Application to GRB 100728A

TL;DR

This paper models GeV emission during X-ray flares in GRB 100728A using late internal shock dynamics, explaining observed spectra through inverse-Compton scattering processes involving relativistic electrons.

Contribution

It introduces a detailed model of GeV emission during X-ray flares, incorporating both synchrotron self-Compton and crossing inverse-Compton scattering in late internal shocks.

Findings

The model successfully reproduces the observed spectral properties of GRB 100728A.

GeV photons are produced by up-scattering of X-ray flare photons by relativistic electrons.

Analytical and numerical results support the late internal shock origin of high-energy emission.

Abstract

Recently, the GeV radiation during the X-ray flare activity in GRB 100728A was detected by Feimi/LAT. Here we study the dynamics and emission properties of collision between two homogeneous shells based on the late internal shock model. The GeV photons can be produced from X-ray flare photons up-scattered by relativistic electrons accelerated by forward-reverse shocks, where involved radiative processes include synchrotron self-Compton and crossing inverse-Compton scattering. By analytical and numerical calculations, the observed spectral properties in GRB 100728A can be well explained.