Spatially resolved X-ray spectroscopy and modeling of the nonthermal emission of the PWN in G0.9+0.1

TL;DR

This study conducts a spatially resolved X-ray spectral analysis of the PWN in G0.9+0.1 and models its nonthermal emission, revealing spectral variations and discrepancies between modeled and observed gamma-ray data.

Contribution

It provides a detailed spatially resolved spectral analysis and applies a leptonic model to interpret the PWN's X-ray and gamma-ray emission, highlighting limitations in current modeling.

Findings

Spectral index increases with distance from the pulsar.

Surface brightness decreases with radius.

Model reproduces X-ray spectra but not gamma-ray data.

Abstract

We performed a spatially resolved spectral X-ray study of the pulsar wind nebula (PWN) in the supernova remnant G0.9+0.1. Furthermore we modeled its nonthermal emission in the X-ray and very high energy (VHE, E > 100 GeV) gamma-ray regime. Using Chandra ACIS-S3 data, we investigated the east-west dependence of the spectral properties of G0.9+0.1 by calculating hardness ratios. We analyzed the EPIC-MOS and EPIC-pn data of two on-axis observations of the XMM-Newton telescope and extracted spectra of four annulus-shaped regions, centered on the region of brightest emission of the source. A radially symmetric leptonic model was applied in order to reproduce the observed X-ray emission of the inner part of the PWN. Using the optimized model parameter values obtained from the X-ray analysis, we then compared the modeled inverse Compton (IC) radiation with the published H.E.S.S. gamma-ray data. The spectral index within the four annuli increases with growing distance to the pulsar, whereas the surface brightness drops. With the adopted model we are able to reproduce the characteristics of the X-ray spectra. The model results for the VHE gamma radiation, however, strongly deviate from the H.E.S.S. data.