Numerical study of propagation of UHECRs: Spectrum, arrival direction, composition

S. Nagataki, K. Sato, D. Allard, K. Kotera, A. Calvez, A. Kusenko, K. Murase, J. Aoi, Y. Dubois, T. Pierog, A. R. Van Vliet, O. Scholten, H. Yoshiguchi

Research output: Contribution to conferencePaperpeer-review


In this paper, simulations of propagation of UHE-protons from nearby galaxies are presented. We found good parameter sets to explain the arrival distribution of UHECRs reported by AGASA and the energy spectrum reported by HiRes. Using a good parameter set, we demonstrated what distribution of arrival direction of UHECRs will be as a function of event numbers. We show that 1000-10000 events are necessary to clearly see the 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 a 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 important when there have been sources of UHE-Nuclei in the Milky Way. Since light nuclei escape from the Milky Way in a short timescale, the chemical composition of UHECRs observed at the Earth can be heavy at the high-energy range as suggested by Auger.

Original languageEnglish (US)
Number of pages4
StatePublished - 2011
Event32nd International Cosmic Ray Conference, ICRC 2011 - Beijing, China
Duration: Aug 11 2011Aug 18 2011


Other32nd International Cosmic Ray Conference, ICRC 2011

All Science Journal Classification (ASJC) codes

  • Nuclear and High Energy Physics


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