Understanding Pulsar Wind Nebulae with the SKA

TL;DR

This paper surveys pulsar wind nebulae (PWNe) and outlines how the Square Kilometer Array (SKA) will transform radio studies of PWNe. It discusses the evolutionary sequence from young, ejecta-embedded bubbles to RS-compressed remnants and bow-shock PWNe, and how radio, X-ray, and gamma-ray emissions trace electron-positron populations, magnetic fields, and transport mechanisms. Open questions address magnetospheric wind generation, acceleration (including magnetic reconnection and striped wind dissipation), and diffusion-advection transport within and beyond PWNe, with an emphasis on disentangling degeneracies through broadband observations. The SKA’s capabilities—enhanced sensitivity, dynamic range, timing, polarization, and frequency coverage—will enable detailed spectral, morphological, and polarimetric studies of a large, diverse PWN sample, providing crucial insights into the origin of the Milky Way’s highest-energy particles and their propagation through the ISM, in synergy with CTA and X-ray missions.

Abstract

Produced by the interaction between the ``pulsar wind'' powered by the rotational energy of a neutron star and its surroundings, the study of pulsar wind nebulae (PWNe) provides vital insight into the physics of neutron star magnetospheres and ultra-relativistic outflows. Spatially-resolved studies of the continuum and polarized radio emission of these sources are vital for understanding the production of $e^\pm$ in the magnetospheres of neutron stars, the acceleration of these particles to $\gtrsim10^{15}~{\rm eV}$ energies, and the propagation of these particles within the PWN as well as the surrounding interstellar medium. The significant improvements in sensitivity, dynamic range, timing capabilities offered by the Square Kilometer Array have the potential to significantly improve our understanding of the origin of some of the highest energy particles produced in the Milky Way.