2011/09/30 by Alexander Kusenko, M.B. Voloshin, M. B. Voloshin
Physics and Astronomy · #Astrophysics and Cosmic Phenomena #Dark Matter and Cosmic Phenomena #Gamma-ray bursts and supernovae #astro-ph.HE #hep-ph
paper · pdf · doi:10.1016/j.physletb.2011.12.045
published as Physics Letters B 707, 255 (2012) · 10 pages, 3 figures; final draft accepted for publication
openalex publication_date 2011/12/21 · arxiv created 2011/12/24 · arxiv updated 2012/01/05 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Astrophysical sources of nuclei are expected to produce a broad spectrum of isotopes, many of which are unstable. An unstable nucleus can beta-decay outside the source into a single-electron ion. Heavy one-electron ions, thus formed, can be excited in their interactions with cosmic microwave background photons, in which case they relax to the ground state with the emission of a gamma ray. Repetitive cycles of excitation and gamma-ray emission can produce an observable feature in the gamma-ray spectrum with a maximum around 8 GeV (for iron). We find that the observed spectrum of Centaurus A is consistent with a substantial flux of nuclei accelerated to 0.1 EeV. A characteristic 5--10 GeV (iron) shoulder in the gamma-ray spectra of various sources can help identify astrophysical accelerators of nuclei or set upper limits on nuclear acceleration.