Ultra-high-energy cosmic rays from the radio lobes of active galactic nuclei

F. Fraschetti, F. Melia

Research output: Contribution to journalArticlepeer-review

22 Scopus citations


In the past year, the HiRes and Auger collaborations have reported the discovery of a high-energy cut-off in the ultra-high-energy cosmic ray spectrum, and an apparent clustering of the highest energy events towards nearby active galactic nuclei. Consensus is building that such ∼1019-10 20 eV particles are accelerated within the radio-bright lobes of these sources, but it is not yet clear how this actually happens. In this paper, we report (to our knowledge) the first treatment of stochastic particle acceleration in such environments from first principles, showing that energies ∼1020 eV are reached in ∼106 yr for protons. However, our findings reopen the question regarding whether the high-energy cut-off is due solely to propagation effects, or whether it does in fact represent the maximum energy permitted by the acceleration process itself.

Original languageEnglish (US)
Pages (from-to)1100-1106
Number of pages7
JournalMonthly Notices of the Royal Astronomical Society
Issue number3
StatePublished - Dec 2008


  • Acceleration of particles
  • Cosmic rays
  • Galaxies: active
  • Galaxies: nuclei
  • Plasmas
  • Turbulence

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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