Current knowledge of the Universe is based on information carried by
electromagnetic radiation, gravitational waves, neutrinos, and cosmic rays (CRs),
taking advantage of a multi-messenger approach. Among those cosmic
messengers, neutrinos have unique features: high-energy astrophysical neutrinos,
originated via collisions of CRs with high-density matter and/or radiation fields, can
cross the Universe preserving the directional information about their production
site, allowing us to unambiguously identify the most efficient sources of particle
acceleration, shedding light on the extreme part of the Universe. During this
seminar, I will provide an overview of the state-of-the-art of neutrino astronomy,
describing the current instruments performing high-energy neutrino astronomy and
their detection principle, as well as summarizing recent experimental results. The
possible astrophysical neutrino emitters will be also discussed, in particular
Gamma-Ray Bursts (GRBs). Indeed, in various propagation stages of their
relativistic jets, CR acceleration and the subsequent emission of neutrinos at
different energies are expected. Their prompt phase has been widely studied over
the years, with no detection of PeV neutrinos coincident with GRBs; however, I will
show why neutrino production in GRBs cannot be excluded, discussing some
alternative theoretical predictions that could be critically tested by future
observations.
