Modeling of the Interaction of GRB Prompt Emission with the Circumburst Medium

TL;DR

This paper develops a numerical model to simulate how gamma-ray burst (GRB) prompt emission interacts with the surrounding medium, affecting observed lightcurves and spectra across multiple wavelengths.

Contribution

It introduces a modified radiation hydrodynamics code that includes nonstationary photoionization and heating effects, providing new insights into GRB afterglow irregularities.

Findings

Total luminosities can reach 10^47 erg/s

Modeling explains irregularities in GRB afterglow lightcurves

Spectra across gamma-ray, X-ray, optical are produced

Abstract

We present methodology and results of numerical modeling of the interaction of GRB prompt emission with the circumburst medium using a modified version of the multi-group radiation hydrocode STELLA. The modification includes the nonstationary photoionization, the photoionization heating and the Compton heating along with the hydrodynamics and radiation transfer. The lightcurves and spectra of the outcoming gamma-ray, X-ray and optical emission are calculated for a set of models (shells) of the circumburst environment, which differ in dimensions, density, density profile, composition, temperature. In some cases total bolometric and optical luminosities can reach 10^47 and 10^43 erg/s respectively. These effects can be responsible for irregularities which are seen on lightcurves of some GRB's X-ray and optical afterglows.