XMM-Newton observations of a superbubble in N 158 in the LMC

TL;DR

This study uses XMM-Newton X-ray observations and spectral analysis to investigate the hot gas in a superbubble within the LMC's N 158 region, revealing supernovae as key energy sources in its evolution.

Contribution

It combines spectral analysis with analytical models to better understand the energy sources and evolutionary state of superbubbles in the interstellar medium.

Findings

Soft X-ray emission from hot shocked gas surrounded by cooler ionized shell.

Stellar winds alone cannot explain the superbubble's energy; supernovae are likely responsible.

Analytical models help determine the superbubble's evolutionary stage.

Abstract

Aims: We study the diffuse X-ray emission observed in the field of view of the pulsar B 0540-69 in the Large Magellanic Cloud (LMC) by XMM-Newton. We want to understand the nature of this soft diffuse emission, which coincides with the superbubble in the HII region N 158, and improve our understanding of the evolution of superbubbles. Methods: We analyse the XMM-Newton spectra of the diffuse emission. Using the parameters obtained from the spectral fit, we perform calculations of the evolution of the superbubble. The mass loss and energy input rates are based on the initial mass function (IMF) of the observed OB association inside the superbubble. Results: The analysis of the spectra shows that the soft X-ray emission arises from hot shocked gas surrounded by a thin shell of cooler, ionised gas. We show that the stellar winds alone cannot account for the energy inside the superbubble, but the energy release of 2 - 3 supernova explosions in the past ~1 Myr provides a possible explanation. Conclusions: The combination of high sensitivity X-ray data, allowing spectral analysis, and analytical models for superbubbles bears the potential to reveal the evolutionary state of interstellar bubbles, if the stellar content is known.