Foreground and source of a cluster of ultra-high-energy cosmic rays

Glennys R. Farrar, Andreas A. Berlind, David W. Hogg

    Research output: Contribution to journalArticlepeer-review


    We investigate the origin of a nearly pointlike cluster of five ultra-high-energy cosmic rays (UHECRs) in the vicinity of R.A. ≈169°2 and decl. ≈56°8, using Sloan Digital Sky Survey and other data. No particular source candidates are found near the estimated source direction, but the direction is exceptional in having a likely merging pair of galaxy clusters at 140 h-1 Mpc, with an unusually low foreground density. Large-scale shocks or another product of the merging galaxy clusters may accelerate the UHECRs, or the merging galaxy clusters may be coincidental and the UHECRs may be accelerated in a rare event of an unexceptional progenitor. Low magnetic deflections in the foreground void may explain why this is the only identified pointlike cluster of so many UHECRs.

    Original languageEnglish (US)
    Pages (from-to)L89-L93
    JournalAstrophysical Journal
    Issue number2 II
    StatePublished - May 10 2006


    • Cosmic rays
    • Large-scale structure of universe

    ASJC Scopus subject areas

    • Astronomy and Astrophysics
    • Space and Planetary Science


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