Ramon Rey-Raposo

ISM-SPP Summer School

Interstellar space is filled with a dilute mixture of charged particles, atoms, molecules and dust grains, called the interstellar medium (ISM). The average particle density of the ISM is 1 cm-3 which represents a density lower than can be created on Earth. The ISM therefore represents a fascinating laboratory to study the physics of highly attenuated gases, chemical processes and atomic, molecular and solid state physics under extreme conditions and numerous other questions of natural sciences. The physics of the ISM plays a crucial role in many areas of astronomy. Galaxy formation and evolution, the formation of stars, cosmic nucleosynthesis, the origin of large complex, prebiotic molecules and the abundance, structure and growth of dust grains which constitute the fundamental building blocks of planets, all these processes are intimately coupled to the physics of the ISM. However, despite its importance, its structure and evolution is still poorly understood. The situation is however improving rapidly. New observations with powerful telescopes have revealed that the ISM is a turbulent, multiphase gas, filled with structures on all resolvable spatial scales. This has lead to a paradigm shift in our understanding of the ISM, where the old equilibrium model is being replaced by a highly dynamical picture of strongly coupled, interacting and turbulently mixed gas phases that are far from equilibrium and that are continuously stirred by processes that are not well understood. This insight has attracted enormous interest in the astronomical community. We enter an era where for the first time enough information is available to gain a deep and comprehensive physical understanding of the ISM and the dynamical processes that govern its evolution. This is of importance for many fields in astronomy. Main aims of this priority program: - combine the expertise of researchers in Germany who work on different aspects of ISM physics - investigate observationally and theoretically how various physical processes interact with one another and shape the ISM - construct a new model of the dynamical, non-linear, multi-phase ISM - The final goal of this priority program is to develop a comprehensive physical understanding of the multi-phase ISM that provides a solid basis for other fields of astrophysics.