Within the framework of the so-called ΛCDM cosmological model, structures form in a hierarchical bottom-up fashion. Understanding how galaxies and galaxy clusters form in this scenario requires a proper description of the complex physical processes that determine the evolution of the cosmic baryons, which fall into the potential wells of the underlying dark matter, cool, and finally condense to form stars. In turn, these processes affect the observable properties of the intergalactic and intracluster media (IGM and ICM) through the action of various feedback processes: gas and metals synthesized by stars are blown out by galactic winds and other gas dynamical processes, and mix with the surrounding IGM/ICM. Furthermore, gas accretion onto supermassive black holes also generates feedback onto the surrounding medium, which has to be consistently coupled with the (magneto-)hydrodynamics. However, a detailed understanding of the underlying physical processes is still extremely limited, as they are currently built on “ad hoc”, empirically constructed sub-grid models. Additional physical processes like magnetic fields and cosmic rays are only rarely and in a very simplified manner included within such models, and typically not self consistently coupled to the other processes. Furthermore, it is even not clear if descriptions of the fluid following Spitzer/Braginsky formulations are adequate (e.g. waves vs. collisions for defining plasma properties).
Here, the "COMPLEX" project is aimed at refining our understanding of the most important physical processes shaping formation and evolution of the cosmic large scale structure, as well as the galaxies and galaxy clusters within them. COMPLEX will focus on the self consistent treatment of fluid properties which describe turbulence, the mixing and the transport processes within the gas, together with its additional components like magnetic fields and so called cosmic rays.
This will boost the insight into the elementary processes defining the fluid properties of the visible matter in the universe and therefore advance our understanding of the evolution of galaxies and galaxy clusters to the next level needed to interpret forthcoming astronomical surveys. Therefor it will contribute to our understanding of the Universe in which we life and give new insights in how the large scale structures and the embedded galaxies within our Universe form and evolve.
