Multiwavelength analysis of the X-ray spur and southeast of the Large Magellanic Cloud

TL;DR

This study investigates the hot interstellar medium in the X-ray spur near the Large Magellanic Cloud's 30 Doradus, revealing multiple plasma components and suggesting gas collision as the heating mechanism rather than stellar activity.

Contribution

It provides a detailed multiwavelength analysis of the X-ray spur, identifying distinct plasma components and proposing a collision-induced heating origin, which is a novel insight into this region.

Findings

Two hot plasma components with different temperatures were identified.

The hotter plasma is concentrated near 30 Dor and the X-ray spur.

The X-ray spur's heating is likely due to gas collision, not stellar activity.

Abstract

Aims: The giant HII region 30 Doradus (30 Dor) located in the eastern part of the Large Magellanic Cloud is one of the most active star-forming regions in the Local Group. Studies of HI data have revealed two large gas structures which must have collided with each other in the region around 30 Dor. In X-rays there is extended emission ($\sim 1$ kpc) south of 30 Dor called the X-ray spur, which appears to be anticorrelated with the HI gas. We study the properties of the hot interstellar medium (ISM) in the X-ray spur and investigate its origin including related interactions in the ISM. Methods: We analyzed new and archival XMM-Newton data of the X-ray spur and its surroundings to determine the properties of the hot diffuse plasma. We created detailed plasma property maps by utilizing the Voronoi tessellation algorithm. We also studied HI and CO data, as well as optical line emission data of H$\alpha$ and [SII], and compared them to the results of the X-ray spectral analysis. Results: We find evidence of two hot plasma components with temperatures of $kT_1 \sim 0.2$ keV and $kT_2 \sim 0.5-0.9$ keV, with the hotter component being much more pronounced near 30 Dor and the X-ray spur. In 30 Dor, the plasma has most likely been heated by massive stellar winds and supernova remnants. In the X-ray spur, we find no evidence of heating by stars. Instead, the X-ray spur must have been compressed and heated by the collision of the HI gas.