Astrophysical and cosmogenic neutrinos: how to trace high-energy interactions in the Universe

The all-sky diffuse astrophysical neutrino spectrum is measured by IceCube with increasing statistical significance, since more than 10 years. In addition, recent observational findings manifest some connections with astrophysical sources, and for the first time a non-electromagnetic image of our galaxy has been delivered by IceCube. In this seminar I will present the most recent experimental results on high-energy neutrinos, and I will deeply discuss the connections with other astrophysical messengers. In particular, I will show how the study of interactions of cosmic rays, in the extragalactic propagation and in the candidate sources, might help in unveiling the origin of high-energy neutrinos and ultra-high-energy cosmic rays. Prospects from future experimental upgrades will be also highlighted, as well as the importance of a multimessenger approach in the modelling of astrophysical sources.