On the origin and survival of ultra-high-energy cosmic-ray nuclei in gamma-ray bursts and hypernovae

Xiang Yu Wang, Soebur Razzaque, Peter Mészáros

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75 Citations (Scopus)


The chemical composition of the ultra-high-energy (UHE) cosmic rays serves as an important clue to their origin. Recent measurements of the elongation rates by the Pierre Auger Observatory hint at the possible presence of heavy or intermediate-mass nuclei in the UHE cosmic rays. Gamma-ray bursts (GRBs) and hypernovae have been suggested as possible sources of the UHE cosmic rays. Here we derive constraints on the physical conditions under which UHE heavy nuclei, if they are accelerated in these sources, can survive in their intense photon fields. We find that in the GRB external shock and hypernova scenarios, UHE nuclei can easily survive photodisintegration. In the GRB internal shock scenario, UHE nuclei can also survive, provided the dissipation radius and/or the bulk Lorentz factor of the relativistic outflow are relatively large, or if the low-energy self-absorption break in the photon spectrum of the prompt emission occurs above several keV. In internal shocks and in the other scenarios, intermediate-mass UHE nuclei have a higher probability of survival against photodisintegration than UHE heavy nuclei such as Fe.

Original languageEnglish
Pages (from-to)432-440
Number of pages9
JournalAstrophysical Journal
Issue number1
Publication statusPublished - 10 Apr 2008
Externally publishedYes


  • Cosmic rays
  • Gamma rays: bursts

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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