HII regions in the Large Magellanic Cloud
Kisetsu Tsuge, Manami Sasaki, Knies Jonathan
Dr. Karl Remeis Sternwarte Bamberg, Friedrich-Alexander-Universität Erlangen-Nürnberg
Multi-wavelength observations are necessary to obtain a comprehensive understanding of the interstellar medium (ISM) evolution because the interstellar space between stars is filled with multi-phased ISM from cold atomic- and molecular gas, and dust to hot diffuse plasma. We focus our studay on the Large Magellanic Cloud (LMC), which is an ideal target for studying galaxy-scale (~ kpc) ISM dynamics and evolution due to its close distance and almost face-on geometry. We conducted an analysis by combining x-ray and radio data to reveal the heating mechanism of diffuse extended x-ray emission. We utilize the wide field of view and high sensitivity of the eROSITA and investigated the physical properties (density n, temperature T, dynamics) of diffuse X-ray in detail toward active star-forming regions N11 and N44. Specifically, we distinguish between shock heating by gas collision and heating by high-mass stars by comparison with cold ISM (atomic hydrogen gas, molecular hydrogen gas). We found observational evidence of massive star formation by tidally driven colliding HI flows over the whole LMC including N11, and N44 (Fukui+17; Tsuge+19;21). Collisions of HI gas flows are also supported by the latest numerical simulation of galactic tidal interaction between the Magellanic Clouds and the near-infrared extinction map (Furuta+21;22) of the LMC. In the vicinities of N11 and N44, high-mass stars have caused the heating of the ISM to X-ray emitting temperatures. The diffuse X-ray emissions over ~ kpc scale around N11 and N44 was also heated to similarly high temperatures. However, the energy input from high-mass stars is not enough to explain the temperature of X-ray. We will discuss the heating mechanism of the diffuse soft X-ray toward N11 and N44 by comparing with the kinetic energy of HI gas collisions in this talk. This study is an essential step forward for understanding the evolution of the ISM, the basic component of the galaxies.