Neutrino astrophysics

Neutrinos of astrophysical origin are messengers produced in stars, in explosive phenomena like core-collapse supernovae, in the accretion disks around black holes, or in the Earth's atmosphere. Their fluxes and spectra encode information on the environments that produce them, but they are modified when neutrinos traverse a medium. Here we summarize our current understanding of neutrino flavour conversion in media and emphasize the importance of this domain for astrophysical observations. We discuss examples of the fundamental properties that astrophysical neutrinos have uncovered, or might reveal in the future.