Extra-galactic sources of high-energy neutrinos

Abstract

The existence of extra-galactic high-energy neutrino sources is implied by observations of ultra-high energy, > 1019 eV, cosmic-rays (UHECRs). Phenomenological, model-independent constraints imposed on the characteristics of the extra-galactic neutrino sources are presented. It is argued that high-energy neutrino telescopes under construction may reach the sensitivity required for detecting the extra-galactic neutrino signal. Such detection will allow to identify the sources of UHECRs and to test models of these sources. It will also provide information on fundamental neutrino properties.