Colliding wind binaries and gamma-ray binaries : relativistic version of the RAMSES code

TL;DR

This paper extends the RAMSES hydrodynamical code to relativistic hydrodynamics to simulate gamma-ray binaries, revealing how relativistic effects influence wind interactions and instabilities.

Contribution

The authors develop a relativistic version of the RAMSES code to simulate gamma-ray binaries, providing new insights into wind interactions under relativistic conditions.

Findings

Kelvin-Helmholtz instability causes mixing and disrupts large-scale structures.

Relativistic corrections have a small but significant impact on wind interaction dynamics.

Simulations show similarities between pulsar-stellar wind interactions and stellar colliding winds.

Abstract

Gamma-ray binaries are colliding wind binaries (CWB) composed of a massive star a non-accreting pulsar with a highly relativistic wind. Particle acceleration at the shocks results in emission going from extended radio emission to the gamma-ray band. The interaction region is expected to show common features with stellar CWB. Performing numerical simulations with the hydrodynamical code RAMSES, we focus on their structure and stability and find that the Kelvin-Helmholtz instability (KHI) can lead to important mixing between the winds and destroy the large scale spiral structure. To investigate the impact of the relativistic nature of the pulsar wind, we extend RAMSES to relativistic hydrodynamics (RHD). Preliminary simulations of the interaction between a pulsar wind and a stellar wind show important similarities with stellar colliding winds with small relativistic corrections.