VegasAfterglow: A High-Performance Framework for Gamma-Ray Burst Afterglows

TL;DR

VegasAfterglow is a high-performance C++ framework that models gamma-ray burst afterglows with detailed physics, flexible parameters, and efficient computation, aiding the interpretation of multi-messenger astronomical data.

Contribution

The paper introduces VegasAfterglow, a novel computational framework that self-consistently models GRB afterglows with high efficiency and flexibility, including complex physical processes and arbitrary environmental profiles.

Findings

Demonstrates high computational efficiency of VegasAfterglow.

Validates the framework's ability to model diverse GRB afterglow scenarios.

Shows potential for interpreting multi-wavelength and multi-messenger observations.

Abstract

Gamma-ray bursts (GRBs) are the most luminous astrophysical transients, known to be associated with core collapse of massive stars or mergers of two compact objects such as two neutron stars. They are followed by multi-wavelength afterglow emission originating from the deceleration of the relativistic jets by the ambient medium. The study of afterglow emission offers crucial insights into the physics of relativistic shocks, the properties of the circumburst environment, the physical and geometrical structure of relativistic jets, as well as the viewing geometry of the observer. We present {\tt VegasAfterglow}, a newly developed, high-performance C++ framework designed for modeling GRB afterglows with flexibility and computational efficiency as key features of design. The framework self-consistently solves forward and reverse shock dynamics and calculates synchrotron (including self-absorption or all spectral regimes) and inverse Compton radiation (including Klein-Nishina corrections); it can handle arbitrary user-defined ambient density profiles, central engine activity histories, viewing angles, and the jet structures of energy, Lorentz factor, and magnetization profiles. It supports both relativistic and non-relativistic regimes and includes lateral jet spreading effects. In this paper, we describe the numerical implementation of the framework and assess its computational performance. Our results demonstrate that {\tt VegasAfterglow} is well-suited for interpreting current and future multi-wavelength observations in the era of multi-messenger astronomy.