Jitter Self-Compton Process: GeV Emission of GRB 100728A

TL;DR

This paper models the GeV emission of GRB 100728A using jitter and jitter self-Compton radiation mechanisms, incorporating a microemitter jet structure to explain multiwavelength observations and the burst duration.

Contribution

It introduces a combined jitter and JSC radiation model with a jet-in-jet structure to explain GRB high-energy emission and duration.

Findings

Reproduces the multiwavelength spectrum of GRB 100728A.

Explains GeV emission as jitter photons scattered by relativistic electrons.

Accounts for GRB duration through microemitter contributions.

Abstract

Jitter radiation, the emission of relativistic electrons in a random and small-scale magnetic field, has been applied to explain the gamma-ray burst (GRB) prompt emission. The seed photons produced from jitter radiation can be scattered by thermal/nonthermal electrons to the high-energy bands. This mechanism is called jitter self-Compton (JSC) radiation. GRB 100728A, which was simultaneously observed by the Swift and Fermi, is a great example to constrain the physical processes of jitter and JSC. In our work, we utilize jitter/JSC radiation to reproduce the multiwavelength spectrum of GRB 100728A. In particular, due to JSC radiation, the powerful emission above the GeV band is the result of those jitter photons in X-ray band scattered by the relativistic electrons with a mixed thermal-nonthermal energy distribution. We also combine the geometric effect of microemitters to the radiation mechanism, such that the "jet-in-jet" scenario is considered. The observed GRB duration is the result of summing up all of the contributions from those microemitters in the bulk jet.