Cosmic neutrinos

The hunt for cosmic neutrinos has effectively just started. Recently, large detectors have been completed and are running, such as IceCube at the South Pole and ANTARES in the Mediterranean sea. Such detectors begin to access the region where neutrino fluxes at energies above 100 GeV are expected from shock and jet acceleration processes in the universe. The expectation for these fluxes comes from common knowledge on particle interactions and from the observation of cosmic rays. As a matter of fact, the sources that accelerate cosmic rays are also the powerful engines that would produce neutrinos. How efficiently this production occurs depends on the nature of sources and of their surrounding environments. The non observation of cosmic events is on one side a source of disappointment, on the other side it represents by itself an important result. If seen in the context of a multi-messenger science, the combination of photon and cosmic ray experiment results brings invaluable information.