Institute for Advanced Study Informal Astrophysics Seminar

ABSTRACT: Recent observations of galaxy clusters reveal new insights into the dynamical and nonthermal processes in the intracluster medium (ICM). Tangential discontinuities (known as cold fronts) are directly seen in high resolution X-ray maps of cool cluster cores. They reveal bulk shear flows which magnetize the plasma, give rise to radio minihalos, and may play a role in resolving the cooling problem. The ICM shows a rich phenomenology of non-thermal radio emission, arguably arising from hadronic cascades involving cosmic-ray protons. While such a secondary signal is too weak to be observed by Fermi, the primary gamma-ray signal from strong shocks should be identifiable.