Recent Progress in Studies of Pulsar Wind Nebulae

TL;DR

This paper reviews recent observational advances across multiple wavelengths in pulsar wind nebulae, highlighting new structures and spectral features that inform theoretical models of these energetic systems.

Contribution

It summarizes recent high-resolution observations and discusses how they have spurred new theoretical developments in understanding pulsar wind nebulae.

Findings

Detection of jets and toroidal structures in X-ray observations

Observation of time-variable knot-like features

Identification of filaments indicating interaction with ejecta

Abstract

The synchrotron-emitting nebulae formed by energetic winds from young pulsars provide information on a wide range phenomena that contribute to their structure. High resolution X-ray observations reveal jets and toroidal structures in many systems, along with knot-like structures whose emission is observed to be time-variable. Large-scale filaments seen in optical and radio images mark instability regions where the expanding nebulae interact with the surrounding ejecta, and spectral studies reveal the presence of these ejecta in the form of thermal X-ray emission. Infrared studies probe the frequency region where evolutionary and magnetic field effects conspire to change the broadband synchrotron spectrum dramatically, and studies of the innermost regions of the nebulae provide constraints on the spectra of particles entering the nebula. At the highest energies, TeV gamma-ray observations provide a probe of the spectral region that, for low magnetic fields, corresponds to particles with energies just below the X-ray-emitting regime. Here I summarize the structure of pulsar wind nebulae and review several new observations that have helped drive a recent resurgence in theoretical modeling of these systems.