PT Journal AU Capozzi, F Saviano, N TI Neutrino Flavor Conversions in High-Density Astrophysical and Cosmological Environments SO Universe JI Universe PY 2022 BP 94 - 23pp VL 8 IS 2 DI 10.3390/universe8020094 LA English DE astrophysical neutrinos; neutrino oscillations; supernovae; neutron star mergers; early Universe; sterile neutrinos AB Despite being a well understood phenomenon in the context of current terrestrial experiments, neutrino flavor conversions in dense astrophysical environments probably represent one of the most challenging open problems in neutrino physics. Apart from being theoretically interesting, such a problem has several phenomenological implications in cosmology and in astrophysics, including the primordial nucleosynthesis of light elements abundance and other cosmological observables, nucleosynthesis of heavy nuclei, and the explosion of massive stars. In this review, we briefly summarize the state of the art on this topic, focusing on three environments: early Universe, core-collapse supernovae, and compact binary mergers. ER