Ultra-High Energy Cosmic Rays and Neutrinos

In this paper, simulation of propagation of UHE-protons from nearby galaxies is presented. We found good parameter sets to explain the arrival distribution of UHECRs reported by AGASA and energy spectrum reported by HiRes. Using a good parameter set, we demonstrated how the distribution of arrival direction of UHECRs will be as a function of event numbers. We showed clearly that 1000-10000 events are necessary to see the clear source distribution. We also showed that effects of interactions and trapping of UHE-Nuclei in a galaxy cluster are very important. Especially, when a UHECR source is a bursting source such as GRB/AGN flare, heavy UHE-Nuclei are trapped for a long time in the galaxy cluster, which changes the spectrum and chemical composition of UHECRs coming from the galaxy cluster. We also showed that such effects can be also important when there have been sources of UHE-Nuclei in Milky Way. Since light nuclei escape from Milky Way in a short timescale, the chemical composition of UHECRs observed at the Earth can be heavy at high-energy range. Finally, we showed how much high-energy neutrinos are produced in GRBs. Since GRB neutrinos do not suffer from magnetic field bending, detection of high-energy neutrinos are very important to identify sources of UHECRs. Especially, for the case of GRBs, high-energy neutrinos arrive at the earth with gamma-rays simultaneously, which is very strong feature to identify the sources of UHECRs.