2004/05/31 by M. Kachelriess, M. Kachelrieß, D. Semikoz · 42 citations
Physics and Astronomy · #Astrophysics #Astrophysics and Cosmic Phenomena #Atomic physics #Auger #Cluster (spacecraft) #Cluster analysis #Cosmic ray #Dark Matter and Cosmic Phenomena #Galaxy #Galaxy cluster #Neutrino Physics Research #Optics #Physics #Pierre Auger Observatory #Point source #Statistics #Ultra-high-energy cosmic ray #astro-ph
paper · pdf · doi:10.1016/j.astropartphys.2005.03.004
published in Astroparticle Physics 23(5), 486-492 (Elsevier BV) · 12 pages, 4 figures; v2 matches version to appear
arxiv created 2005/03/17 · openalex publication_date 2005/04/10 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We have calculated the probability that the clustering of arrival directions of ultra-high energy cosmic rays (UHECRs) is consistent with a finite number of uniformly distributed proton sources. The case of a continuous source distribution is reached only for an unrealisticly high source density, ns≫ 10-2/Mpc3. Even for densities as large as ns=10-3/Mpc3, less than half of the observed cluster are on average by chance. For the best-fit value ns=(1-3)× 10-5/Mpc3 derived from the AGASA data, the probability that at least one observed cluster is from a true point source is larger than 99.97%, while on average almost all observed clusters are true. The best-fit value found is comparable to the density of AGNs and consistent with the recent HiRes stereo data. In this scenario, the Pierre Auger Observatory will not only establish the clustering of UHECRs but also determine the density of UHECR sources within a factor of a few after one year of data taking.