Observations of X-rays and Thermal Dust Emission from the Supernova Remnant Kes 75

TL;DR

This study combines infrared and X-ray observations of supernova remnant Kes 75 to analyze dust emission and gas properties, suggesting a Wolf-Rayet progenitor and providing flux limits for the pulsar wind nebula.

Contribution

First combined infrared and X-ray analysis of Kes 75, constraining dust-to-gas ratio and modeling the remnant's thermal emission with implications for its progenitor type.

Findings

Dust-to-gas mass ratio ~0.001

Two-component thermal X-ray model fits the data

Infrared flux upper limits for pulsar wind nebula

Abstract

We present Spitzer Space Telescope and Chandra X-ray Observatory observations of the composite Galactic supernova remnant Kes 75 (G29.7-0.3). We use the detected flux at 24 microns and hot gas parameters from fitting spectra from new, deep X-ray observations to constrain models of dust emission, obtaining a dust-to-gas mass ratio M_dust/M_gas ~0.001. We find that a two-component thermal model, nominally representing shocked swept-up interstellar or circumstellar material and reverse-shocked ejecta, adequately fits the X-ray spectrum, albeit with somewhat high implied densities for both components. We surmise that this model implies a Wolf-Rayet progenitor for the remnant. We also present infrared flux upper limits for the central pulsar wind nebula.