Studying the multiphase interstellar medium in the Large Magellanic Cloud with SRG /eROSITA: I. Analysis of diffuse X-ray emission

Mayer M, Sasaki M, Haberl F, Tsuge K, Fukui Y, Maitra C, Filipović MD, Smeaton ZJ, Staveley-Smith L, Koribalski B, Points S, Kavanagh P (2025)

Publication Type: Journal article

Publication year: 2025

Journal

Astronomy & Astrophysics EDP Sciences

Book Volume: 700

Article Number: A137

DOI: 10.1051/0004-6361/202554971

Abstract

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.

Authors with CRIS profile

Martin Mayer Dr.Karl-Remeis-Sternwarte Bamberg, Astronomisches Institut Manami Sasaki Professur für Multiwellenlängenastronomie

Involved external institutions

Max-Planck-Institut für extraterrestrische Physik (MPE) / Max Planck Institute for Extraterrestrial Physics DE Germany (DE) Gifu University / 岐阜大学 JP Japan (JP) Nagoya University / 名古屋大学 JP Japan (JP) University of Western Sydney AU Australia (AU) University of Western Australia (UWA) AU Australia (AU) Cerro Tololo Inter-American Observatory (CTIO) CL Chile (CL) Maynooth University IE Ireland (IE)

How to cite

APA:

Mayer, M., Sasaki, M., Haberl, F., Tsuge, K., Fukui, Y., Maitra, C.,... Kavanagh, P. (2025). Studying the multiphase interstellar medium in the Large Magellanic Cloud with SRG /eROSITA: I. Analysis of diffuse X-ray emission. Astronomy & Astrophysics, 700. https://doi.org/10.1051/0004-6361/202554971

MLA:

Mayer, Martin, et al. "Studying the multiphase interstellar medium in the Large Magellanic Cloud with SRG /eROSITA: I. Analysis of diffuse X-ray emission." Astronomy & Astrophysics 700 (2025).

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