3D Relativistic MHD Simulations of Pulsar Bow Shock Nebulae

TL;DR

This paper presents 3D relativistic MHD simulations of pulsar bow shock nebulae, analyzing their emission, turbulence, and cosmic ray acceleration to better understand their structure and role in high-energy astrophysics.

Contribution

It introduces detailed 3D relativistic MHD simulations of pulsar bow shock nebulae, exploring their emission, turbulence, and cosmic ray dynamics, which advances modeling of these systems.

Findings

Emission signatures depend on wind structure and magnetisation

Current sheets channel cosmic rays and influence particle escape

Turbulence and magnetic amplification vary with nebula parameters

Abstract

Pulsars out of their parent SNR directly interact with the ISM producing so called Bow-Shock Pulsar Wind Nebulae, the relativistic equivalents of the heliosphere/heliotail system. These have been directly observed from Radio to X-ray, and are found also associated to TeV halos, with a large variety of morphologies. They offer a unique environment where the pulsar wind can be studied by modelling its interaction with the surrounding ambient medium, in a fashion that is different/complementary from the canonical Plerions. These systems have also been suggested as the possible origin of the positron excess detected by AMS and PAMELA, in contrast to dark matter. I will present results from 3D Relativistic MHD simulations of such nebulae. On top of these simulations we computed the expected emission signatures, the properties of high energy particle escape, the role of current sheets in channeling cosmic rays, the level of turbulence and magnetic amplification, and how they depend on the wind structure and magnetisation.