X-Ray and high energy flares from late internal shocks of gamma-ray bursts

TL;DR

This paper models X-ray and high-energy flares in gamma-ray bursts using late internal shocks, constraining shell properties and predicting detectable high-energy emission via synchrotron self-Compton processes.

Contribution

It provides a detailed dynamical model of late internal shocks in GRBs and links observational features of X-ray flares to properties of the central engine.

Findings

Constraints on pre-collision shell properties derived from X-ray flare observations

Predicted high-energy flare fluxes up to 10^{-8} erg cm^{-2}s^{-1}

High-energy flares are potentially detectable by Fermi LAT

Abstract

We study afterglow flares of gamma-ray bursts (GRBs) in the framework of the late internal shock (LIS) model based on a careful description for the dynamics of a pair of shocks generated by a collision between two homogeneous shells,. First, by confronting the model with some fundamental observational features of X-ray flares, we find some constraints on the properties of the pre-collision shells that are directly determined by the central engine of GRBs. Second, high energy emission associated with X-ray flares, which arises from synchrotron self-Compton (SSC) emission of LISs, is investigated in a wide parameter space. The predicted flux of high energy flares may reach as high as $\sim 10^{-8}\rm erg cm^{-2}s^{-1}$, which is likely to be detectable with the Large Area Telescope (LAT) aboard \textit{the Fermi Space Telescope}