The Physical Processes Of Star Formation And The Properties Of The Interstellar Medium In The Magellanic Clouds

The Interstellar Medium (ISM) harbours processes that play key roles in the evolution of galaxies. It hosts the signatures of the many feedback processes induced by star formation, including the metal enrichment (metallicity). This work aims to study the structure of the different gas and dust phases in star-forming regions, the cooling and heating processes at play, and how they are affected by the metallicity.We focus on the Large and Small Magellanic Clouds (LMC and SMC), two dwarf satellites of the Milky Way: they have sub-solar metallicities, and their proximity allows us to have spatially detailed observations of star-forming regions. We complete those observations with the Dwarf Galaxy Sample (DGS) observations, that target 48 mostly unresolved dwarf galaxies of the Local Universe with different physical conditions. We predict the emission lines [OIII] 88μm, [OI] 63μm, [CII] 157μm, and the Spitzer/MIPS 24μm and 70μm bands using photoionization model grids. We develop a new method based on those tracers that infers the physical conditions of star-forming regions and we investigate the proportion of neutral phase of the star-forming ISM with respect to the ionized phase. We also calibrate a relation between [OIII] 88μm and MIPS 24μm that holds for our resolved regions and the unresolved DGS, which can be useful to prepare future observations.To study the heating and cooling processes, we focus on the neutral region, and compared two classical tracers of the heating in this phase, the PAHs emission and the total infrared luminosity to the main cooling lines, [CII] 157μm and [OI] 63μm. We show that in the LMC the PAHs are better tracers of heating in the neutral ISM.