Diffuse PeV neutrino emission from ultraluminous infrared galaxies.

Ultraluminous infrared galaxies (ULIRGs) are the most luminous and intense starburst galaxies in the Universe. Both their star formation rates and their gas surface mass densities are very high, implying a high supernova rate and an efficient energy conversion of energetic protons. A small fraction of these supernovae are the so-called hypernovae, with a typical kinetic energy ~1052 erg and a shock velocity > 109 cms-1. The strong shocks driven by hypernovae are able to accelerate cosmic ray protons up to 1017 eV. These energetic protons lose a good fraction of their energy through proton-proton collision when ejected into very dense interstellar media, and as a result, produce high-energy neutrinos ( < 5 PeV). Recent deep infrared surveys provide solid constraints on the number density of ULIRGs across a wide redshift range Oszs 2.3, allowing us to derive the flux of diffuse neutrinos from hypernovae. We find that at PeV energies, the diffuse neutrinos contributed by ULIRGs are comparable to atmosphere neutrinos with the flux of 2 X 10~9 GeVcm~2s_I sr~' by assuming the injected cosmic ray spectrum to be dNp/ds'p [ABSTRACT FROM AUTHOR]