2007/10/07 by Hajime Takami, Katsuhiko Sato · 1 citation
Physics and Astronomy · #Astrophysics and Cosmic Phenomena #Dark Matter and Cosmic Phenomena #Radio Astronomy Observations and Technology #astro-ph
paper · pdf · doi:10.1016/j.astropartphys.2007.10.001
published as Astropart.Phys.28:529-539,2008 · 19 pages, 8 figures, accepted for publication in Astroparticle Physics
arxiv created 2007/10/07 · openalex publication_date 2007/11/09 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We discuss the possibility of accurately estimating the source number density of ultra-high-energy cosmic rays (UHECRs) using small-scale anisotropy in their arrival distribution. The arrival distribution has information on their source and source distribution. We calculate the propagation of UHE protons in a structured extragalactic magnetic field (EGMF) and simulate their arrival distribution at the Earth using our previously developed method. The source number density that can best reproduce observational results by Akeno Giant Air Shower Array is estimated at about 10-5 \rm Mpc-3 in a simple source model. Despite having large uncertainties of about one order of magnitude, due to small number of observed events in current status, we find that more detection of UHECRs in the Auger era can sufficiently decrease this so that the source number density can be more robustly estimated. 200 event observation above 4 × 1019 \rm eV in a hemisphere can discriminate between 10-5 and 10-6 \rm Mpc-3. Number of events to discriminate between 10-4 and 10-5 \rm Mpc-3 is dependent on EGMF strength. We also discuss the same in another source model in this paper.