Multiwavelength study of the HII region LHA 120-N11 in the Large Magellanic Cloud with eROSITA

¹ Dr. Karl Remeis Observatory, Erlangen Centre for Astroparticle Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg, Sternwartstraße 7, 96049 Bamberg, Germany
e-mail: kisetsu.tsuge@fau.de
² Max-Planck-Institut für extraterrestrische Physik, Gießenbachstraße 1, 85748 Garching, Germany
³ NSF’s NOIRLab/Cerro Tololo Inter-American Observatory, Casilla 603, La Serena, Chile
⁴ Western Sydney University, Locked Bag 1797, Penrith South DC, NSW 2751, Australia
⁵ International Centre for Radio Astronomy Research (ICRAR), University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
⁶ ARC Centre of Excellence for All Sky Astrophysics (ASTRO 3D), Australia
⁷ Australia Telescope National Facility, CSIRO Astronomy and Space Science, PO Box 76, Epping, NSW 1710, Australia
⁸ Argelander-Institut für Astronomie (AIfA), Universität Bonn, Auf dem Hügel 71, 53121 Bonn, Germany

Received: 27 September 2023
Accepted: 11 March 2024

Abstract

Aims. We studied the diffuse X-ray emission around the HII region LHA 120-N11, which is one of the most active star-forming regions in the Large Magellanic Cloud. We want to determine the nature of the diffuse X-ray emission and improve our understanding of its origin including related interactions with the cold interstellar medium.

Methods. We analyzed the diffuse X-ray emission observed with the extended Roentgen Survey with an Imaging Telescope Array (eROSITA) on the Spectrum-Roentgen-Gamma mission to determine the physical properties of the hot diffuse X-ray emission. Four spectral extraction regions were defined based on the morphology of the X-ray emission. We also studied HI and CO data, as well as Hα line emission in the optical, and compared them with the properties of the diffuse X-ray emission.

Results. The X-ray emission in the four regions is well fitted with an absorbed model consisting of thermal plasma models (vapec) yielding temperatures of kT = ~0.2 keV and kT = 0.8–1.0 keV. The comparison of the X-ray absorption column density and the hydrogen column density shows that the X-ray dark lane located north of N11 is apparently caused by the absorption by HI and CO clouds. By estimating the energy budget of the thermal plasma, we also investigated the heating mechanism of the X-ray emitting plasma. The energy of the diffuse X-ray emission in the superbubble which is a star-forming bubble with a radius of ~120 pc including OB associations LH9, LH10, LH11, and LH13 can be explained by heating from high-mass stars. In the surrounding regions we find that the energy implied by the X-ray emission suggests that additional heating might have been caused by shocks generated by cloud–cloud collisions.