Spatially-Dependent Modelling of Pulsar Wind Nebula G0.9+0.1

TL;DR

This paper introduces a detailed, multi-zone, time-dependent model for pulsar wind nebula G0.9+0.1 that accounts for spatial and temporal variations in magnetic fields, particle transport, and radiative processes to better fit observed spectra and size data.

Contribution

The authors develop a novel multi-zone, time-dependent leptonic model that incorporates spatially-dependent magnetic fields and particle transport to improve spectral and size predictions.

Findings

Model accurately reproduces observed spectrum and size of G0.9+0.1.

Simultaneous fitting constrains key physical parameters.

Spatially-dependent modeling enhances understanding of nebular evolution.

Abstract

We present results from a leptonic emission code that models the spectral energy distribution of a pulsar wind nebula by solving a Fokker-Planck-type transport equation and calculating inverse Compton and synchrotron emissivities. We have created this time-dependent, multi-zone model to investigate changes in the particle spectrum as they traverse the pulsar wind nebula, by considering a time and spatially-dependent B-field, spatially-dependent bulk particle speed implying convection and adiabatic losses, diffusion, as well as radiative losses. Our code predicts the radiation spectrum at different positions in the nebula, yielding the surface brightness versus radius and the nebular size as function of energy. We compare our new model against more basic models using the observed spectrum of pulsar wind nebula G0.9+0.1, incorporating data from H.E.S.S. as well as radio and X-ray experiments. We show that simultaneously fitting the spectral energy distribution and the energy-dependent source size leads to more stringent constraints on several model parameters.