Gamma-Ray Burst afterglow scaling coefficients for general density profile

TL;DR

This paper introduces a new computational code to model GRB afterglows with arbitrary density profiles, extending previous models and providing detailed fits to observed data, including GRB 970508.

Contribution

The authors develop a flexible code for reconstructing spectra and light curves from complex fluid configurations, extending afterglow models to general density profiles.

Findings

Extended scaling coefficients to general density profiles.

Re-derived physical parameters of GRB 970508.

Validated code against existing models and observations.

Abstract

Gamma-ray burst (GRB) afterglows are well described by synchrotron emission originating from the interaction between a relativistic blast wave and the external medium surrounding the GRB progenitor. We introduce a code to reconstruct spectra and light curves from arbitrary fluid configurations, making it especially suited to study the effects of fluid flows beyond those that can be described using analytical approximations. As a check and first application of our code we use it to fit the scaling coefficients of theoretical models of afterglow spectra. We extend earlier results of other authors to general circumburst density profiles. We rederive the physical parameters of GRB 970508 and compare with other authors