Dissecting the X-ray Emission in the Young Planetary Nebula NGC 7027

TL;DR

This study analyzes high-resolution X-ray observations of the young planetary nebula NGC 7027, revealing plasma properties, spatial distribution, and the importance of accounting for nebular absorption to understand X-ray emission in PNe.

Contribution

It provides a detailed spatial and spectral analysis of NGC 7027's X-ray emission using new and archival Chandra data, highlighting the role of nebular absorption in plasma characterization.

Findings

X-ray plasma temperature ~3.6 MK

X-ray luminosity ~7×10^31 erg/s

No significant evolution over 14 years

Abstract

We present analysis of a second observation of the young planetary nebula (PN) NGC 7027 by the Chandra X-ray Observatory. This latest 59.2 ks exposure with ACIS-S was acquired approximately 14 years after the initial 18.2 ks ACIS-S observation, and the improved photon statistics allow us to perform a detailed spatial and spectral analysis of the X-ray emission. Comparison with multiwavelength imaging of NGC 7027 reveals a strong anti-correlation between extinction across the nebula and the soft band X-ray emission. Dissecting the X-ray emission into low- and high-extinction regions results in more robust characterization of the plasma spectral properties. We determine that the X-ray emitting plasma has a temperature of $\sim3.6$ MK, is deficient in Fe, and has an X-ray luminosity of $L_{\rm X}\sim7\times10^{31}{\rm ~erg~s}^{-1}$, all of which are generally consistent with the plasma properties found in PN hot bubbles. We find no evidence of evolution in the X-ray surface brightness over the 14 year baseline between Chandra observations. Our analysis underscores the importance of accounting for nebular absorption of the X-ray emission in accurately determining plasma properties for hot bubbles within PNe.