2025A&A...700A.137M

Context. The Large Magellanic Cloud (LMC), being a nearby and actively star-forming satellite galaxy of the Milky Way, is an ideal site to observe the multiphase interstellar medium (ISM) of a galaxy across the electromagnetic spectrum.
Aims. We aimed to exploit the available SRG/eROSITA all-sky survey data to study the distribution, composition and properties of the diffuse X-ray emitting hot gas in the LMC.
Methods. We constructed multiband X-ray images of the LMC, reflecting the morphology and temperatures of the diffuse hot gas. By performing spatially resolved X-ray spectroscopy of 175 independent regions, we constrained the distribution, temperature, mass, energetics and composition of the hot ISM phase throughout the galaxy, while also testing for the presence of X-ray synchrotron emission. We combined our constraints with multiwavelength data to obtain a comprehensive view of the different ISM phases.
Results. We measure a total X-ray luminosity of the hot ISM phase of 1.9 × 10³⁸ erg s^–1 (0.2-5.0 keV band), and constrain its thermal energy to around 9 × 10⁵⁴ erg. The typical density and temperature of the X-ray emitting plasma are around 5 × 10^–3 cm^–3 and 0.25 keV, respectively, with both exhibiting broad peaks in the southeast of the LMC. The observed degree of X-ray absorption correlates strongly with the distribution of foreground H I gas, whereas a spatial anticorrelation between the hot and cold ISM phases is visible on sub-kpc scales within the disk. The abundances of light metals show a strong gradient throughout the LMC, with the north and east exhibiting a strong α-enhancement, as expected from observed massive stellar populations there. In contrast, the enigmatic “X-ray spur” exhibits a local deficit in α-elements, and a peak in hot-gas pressure at P/k ∼ 10⁵ K cm^–3, consistent with a dominant energy input through tidally driven gas collisions. Finally, we tentatively identify spectroscopic signatures of nonthermal X-ray emission from the supergiant shell LMC 2, although contamination by straylight cannot be excluded.