Fitting Pulsar Wind Tori. II. Error Analysis and Applications

TL;DR

This paper applies a torus fitting method to pulsar wind nebulae in Chandra data, quantifies uncertainties, and demonstrates the robustness of symmetry axis and spin inclination measurements for understanding PWN geometry.

Contribution

It extends previous torus fitting techniques by providing a detailed error analysis and applying it systematically to Chandra observations of PWNe.

Findings

Symmetry axis $$ of PWNe is well determined and model-independent.

Robust measurements of spin inclination $$ are achieved.

Uncertainties are characterized through statistical and systematic error analysis.

Abstract

We have applied the torus fitting procedure described in Ng & Romani (2004) to PWNe observations in the Chandra data archive. This study provides quantitative measurement of the PWN geometry and we characterize the uncertainties in the fits, with statistical errors coming from the fit uncertainties and systematic errors estimated by varying the assumed fitting model. The symmetry axis $\Psi$ of the PWN are generally well determined, and highly model-independent. We often derive a robust value for the spin inclination $\zeta$. We briefly discuss the utility of these results in comparison with new radio and high energy pulse measurements