Le 15 novembre 2019
De 10h30 à 12h00
Marc-Antoine Miville-Deschênes
CEA
Today we fundamentally do not understand the process of formation of collapsed structures in the Universe. How the injection of energy, mass, and metals from stars and galaxies play against the forces of cooling, condensation, turbulence, magnetic fields, and gravity to establish the Universe we see remains an open question in even the broadest of strokes. The interstellar medium (ISM) is the reservoir from which every star is formed and its structure determines how galaxies are formed and change over the history of the Universe. The ISM is also the laboratory where the complex multi-scale and multi-process physics at play in the formation of structures throughout the Universe can be studied in detail within our own Galaxy. Therefore the ISM is a major key to understand the evolution of baryons in the Universe in general.
Because it surrounds us, interacts with almost every wavelength of light, and acts on all scales, the study of the ISM has always been one of synthesis across theories, data, wavelengths, and expertise. This synthesis has grown richer and more complex in recent years, especially given the increasing size of datasets. The deep interconnectivity inherent to this subfield presents a dilemma; no one research group has both the breadth and depth to sharpen and unify our vision. Progress requires cooperation over a very large range of expertise. To meet these challenges we have gathered scientists with a wide range of expertise and create a CNRS International Research Network named « Interstellar Institute ». This group has started to meet in 2017 and several new results have already stemmed from this collaboration. In this talk I will present some of those results, on the 3D structure of the local ISM, on the development of new methods based on regularized optimization, machine vision or neural networks to study the complex multi-phase and magnetized interstellar turbulence, and on the essential role numerical simulations play in understanding the evolution of baryons. I will conclude by reflecting on how this new way of doing research, in a large-scale and open way, is bringing value added, and on how it increases our understanding, the identification of the next big questions and the means to tackle them.