Hidden Source of High Energy Neutrinos in Collapsing Galactic Nucleus

We propose a model of a short-lived extremely powerful source of high energy neutrinos. It is formed as a result of dynamical evolution of a galactic nucleus prior to its collapse into the massive black hole. A dense central stellar cluster in the galactic nucleus on the large stage of evolution consists of compact stars (neutron stars and stellar mass black holes). This cluster is sinked deep into the massive gas envelope produced in the collisions of the primary stellar population. The frequent collisions of remaining neutron stars in central stellar cluster result in a creation of ultrarelativistic fireballs and shock waves. They produce the rarefied cavern with external shell and quasi-stationary external shock. The particles are effectively accelerated in the cavern and, due to pp-collisions in the gas envelope, they produce high energy neutrinos. All high energy particles, except neutrinos, are absorbed in the thick envelope. Duration of active stage is ∼10 yr, the number of the sources can be ~10 per cosmological horizon. High energy neutrino signal can be detected by underground neutrino telescope with effective area ∼1 km^2.