Lecturer: Mr. Elad Zinger Affiliation: Racah Institute of Physics, The Hebrew University of Jerusalem Abstract: We discuss the structure and properties of galaxy clusters with an emphasis on the dynamical state of the clusters. We show that inflowing gas streams play an important role in determining the properties of the ICM and whether a cluster is dynamically relaxed or disturbed. In addition, collisions of inflowing streams are shown to be a viable mechanism for generating shocks and 'Cold Fronts' in the ICM. The hot ICM, found behind the virial accretion is shock, is found to extend out to R_shock = (2□-3)R_vir. This implies that the influence of the ICM on galaxies in its vicinity via ram-pressure stripping extends farther out than previously assumed. In this way the presence of quenched galaxies, preferentially discs, at the outskirts of galaxy clusters can be explained, as well as the delayed quenching of satellites compared to central galaxies. Additional details of the upcoming Astrophysics' seminars can be found on the following link. ‏האירוע הזה כולל שיחת וידאו ב-Google Hangouts. הצטרף: https://hangouts.google.com/hangouts/_/mail.huji.ac.il/astrophysics?hceid=bWFpbC5odWppLmFjLmlsX2c0czhydDlpcmhwZzRvdGNybWIzZGFqcjdvQGdyb3VwLmNhbGVuZGFyLmdvb2dsZS5jb20.cvlsamr01tbpdq17lkoo16bu2c&hs=121