Pauli Center Blackboard Seminar

# Pauli Lecture: Understanding the strange appeareance of the largest objects of the universe

## by Julius Donnert (INAF & Inst. di Radioastronomia, Bologna)

Thursday, November 26, 2015 from to (Europe/Berlin)
at DESY Hamburg ( Sem. room 2 )
 Description Galaxy clusters are the largest gravitationally bound objects in our Universe.They form in a hierarchical process through merging of smaller structures, which drive shocks and turbulence in the intra-cluster-medium, a thin hot plasma in the center of clusters. The ongoing revolution in radio astronomy, driven by large interferometers like LOFAR, allows us to observe signatures of these processes with unprecedented fidelity and thus provides unique insights into an extreme astrophysical environment. In this year's Pauli lecture, I will motivate how our current cosmological model predicts the formation of clusters through the hierarchical clustering of dark matter halos. I will then highlight recent developments in radio observations of galaxy clusters. Finally, I will present how these discoveries fundamentally challenge our theoretical understanding of weakly collisional plasmas on the largest scales. This also requires the development of new numerical methods that demand exa-scale computing. Material: