Neutrinos from dense environments

Neutrinos from dense environments are unique laboratories for astrophysics, particle physics and many-body physics. They tell us about the last stages of the gravitational core-collapse and the explosion of massive stars. These elusive particles are also tightly linked to heavy elements synthesis in gravitational core-collapse supernovae and binary neutron star mergers, or play a pivotal role at the MeV epoch during the Universe expansion. We highlight theoretical and observational aspects of this interesting domain, in particular for the future measurement of neutrinos from the next core-collapse supernova, and of the diffuse supernova background, whose discovery might lie in the forthcoming future.