Neutrino dating of the galaxy formation epoch

High energy neutrinos, owing to their penetration capability, can serve as a probe of the remote past of the Universe. The possible investigations include a search for pregalactic objects and for the bright phase of galactic evolution, i.e. comparatively short time interval when luminosities of galaxies were very high. If the bright phase took place at redshifts as large as z approx. > 10, the use of high-energy neutrinos is especially efficient because, in addition to an enhanced generation of ultra-high energy particles during the bright phase, there was a large density of relic photons; collisions of the former with the later generate charged pions which produce, in a chain of decays, neutrinos. The expected flux of neutrinos with energies Esub(v) > 1015 eV is evaluated for a case when the bright phase took place at z approx. > 10. The accompanying gamma-ray radiation produced by interactions of cosmic rays with gas (both in galaxies and in intergalactic space) and with relic radiation does not exceed the observed intensity of isotropic gamma-ray background. The expected intensity of neutrino fluxes is such that it can be measured by means of an acoustic version of the DUMAND array widely discussed at present. The paper also touches upon some topics of the early evolution of galaxies and the acceleration of particles to ultra-high energies at the bright phase of galactic evolution. (orig.)