The small-scale processes of star formation and feedback are tightly linked to galaxy evolution through a multi-scale matter cycle. During this cycle, stars form from the interstellar medium (ISM), and reshape it by injecting energy, momentum and metals, completing a feedback loop. The duration and the efficiency of the successive stages of this cycle vary across and within galaxies, but the exact physical mechanisms driving it remain elusive. A detailed understanding of the small-scale mechanisms regulating star formation and feedback is the key for a full comprehension of galaxy evolution. Increasingly detailed ISM models and multi-wavelength observations now enable us to build a comprehensive view of this multi-scale cycle. As our nearest neighbor, the Large Magellanic Cloud (LMC) has been observed in a broad range of wavelengths and offers the perfect combination between high spatial resolution and a large field of view. It is the ideal laboratory to examine in detail the interplay between stellar activity and the ISM.
I will present a detailed study of the multi-phase ISM of the LMC using multi-wavelength tracers (including Halpha, OIII, SII, HI, 24 μm, CO), tracing all phases of the ISM, from the ionised to the molecular gas. By using MULTIGRIS, a new Bayesian code designed to constrain multi-component ionization models, I have determined key physical parameters of HII regions (e.g., density, ionization parameters, escape fractions of ionizing photons). Connecting the multi-phase ISM structure of individual regions with their evolutionary timeline enables us to characterize the mechanisms driving star formation and feedback, as a function of the local physical properties. Understanding how the detailed physical processes driving this cycle on ~10pc scales regulate the global, galactic-scale properties will serve as a major reference for high-redshift galaxy studies, where spatial resolution is far more limited.
