Where are the gamma-rays?
Denis Wittor (Hamburg University)
Tuesday 15/12/2020 @ 14:00, Sala IV piano Battiferro
Galaxy cluster host the largest particle accelerators in the Universe: Shock waves in the Intracluster Medium, that accelerate particles to high energies. Extended and diffuse synchrotron emission proves the existence of shock accelerated cosmic-ray electrons. However, a signal of shock accelerated cosmic-ray protons, in form of gamma-rays, remains undetected. The famous "missing gamma-ray problem " directly challenges the shock acceleration mechanism in the ICM. Over the last decade, various studies have improved our knowledge on the physics that govern the shock acceleration processes in the ICM. These new models are able to explain the non-detection of gamma-rays. In this contribution, I will present the advances in solving the missing gamma-ray problem.