Invited Talk - Plenary
Multi-Messenger Astronomy with Gamma Rays and Neutrinos
In addition to photons, new messengers from the Universe provide us with complementary information and give us a unique view onto the high-energy Universe. Those messengers include cosmic rays and high-energy neutrinos. Cosmic rays are charged particles (mainly protons) that bombard the Earth from all directions reaching energies up to 10 million times what can be achieved by the most powerful man-made accelerator, the LHC. Their origin is difficult to trace, because cosmic rays are deflected by magnetic fields on their journey from their source to Earth. However, cosmic rays produce gamma-ray photons and neutrinos in interactions with matter and photon fields in or close to their source. Being neutral those secondary particles can travel undeflected and ultimately point back to the source. While gamma rays are not solely produced in interactions of cosmic ray protons, neutrinos provide a smoking-gun signature for acceleration of protons (or heavier nuclei). Candidate cosmic-ray source classes include active galactic nuclei (AGN), Starburst Galaxies, Tidal Disruption Events (TDEs) and Gamma-ray Bursts (GRBs). I will put the potential acceleration sites in the context of recent observations of gamma-ray and neutrino emission.