GSI-Kolloquium: High Energy Astrophysics: Cosmic Rays, Gamma-Rays and Neutrinos

High Energy Astrophysics is a interdisciplinary research field crossing modern astronomy, physics and cosmology. The major objective is to study astronomical phenomena in their most energetic and extreme forms. It addresses a diversity of observational and theoretical topics related to the acceleration, propagation and radiation of relativistic particles in different astronomical environments. Cosmic Rays were first discovered in 1912. After almost 100 years of research their origin is still an open question, especially at the highest energies. This situation could easily be solved if the trajectories of Cosmic Rays could be followed back to their sources. The presence of extragalactic magnetic field strongly challenges this possibility and indirect paths must be followed, seeking for clues in other astrophysical messengers. This requires strong synergies between different research areas, including Origin of Cosmic Rays, Gamma-Ray Astronomy and efforts for the establishment of new observational windows, seeking for example for cosmic high energy Neutrinos. This seminar is devoted to the status of High Energy Astrophysics (at energies larger than 100 GeV) through a selection of results obtained using different techniques. Special emphasis will be given to the question of the origin of Cosmic Rays and the synergies between the different approaches.