The formation of stars is a fundamental aspect of how matter evolves in the Universe. It dictates timescales, chemical and structure evolution of baryons. It is the respiration of galaxies; star formation makes galaxies “boil”, bubble and fragment. Without it the Universe would have ended up in a sterile collection of gravitational singularities. Star formation creates structures as a result of specific non-linear physical processes. In that respect, a galaxy is a complex, self-organized system. This complexity is revealed by the multi-scale and multi-phase nature of the interstellar medium. This talk will be about the use of multi-wavelength, and especially hyper-spectral data, to uncover aspects of the energy and matter cascade of the interstellar medium of the Milky Way. I will present how such data (dust, CO, 21 cm) and their comparison to numerical simulations, can be used to get a clearer view of the evolution of diffuse matter in a galaxy like the Milky Way. In particular I will present recent results on the use of dust scattering to trace the cascade of the ISM cascade down to very small scales, as well as our current work on the analysis of large 21 cm datasets to uncover the first steps of the formation of cold and dense structures in the diffuse ISM.
Organization: M. Galametz