Origin of the ankle in the ultrahigh energy cosmic ray spectrum, and of the extragalactic protons below it

2015/05/31 by M. Unger, Michael Unger, Glennys R. Farrar +1 · 2 citations
Physics and Astronomy · #Astrophysics #Astrophysics and Cosmic Phenomena #Composition (language) #Cosmic ray #Dark Matter and Cosmic Phenomena #Energy (signal processing) #Energy spectrum #Neutrino #Neutrino Physics Research #Nuclear physics #Physics #Quantum mechanics #Range (aeronautics) #Spectrum (functional analysis) #astro-ph.HE

paper · pdf · doi:10.1103/physrevd.92.123001

published as Phys. Rev. D 92, (2015) 123001 · extended discussion of source parameters, accepted for publication in PRD

arxiv created 2015/11/04 · openalex publication_date 2015/12/01 · arxiv updated 2015/12/04 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05

Abstract

The sharp change in slope of the ultrahigh energy cosmic ray (UHECR) spectrum around 10^18.6 eV (the ankle), combined with evidence of a light but extragalactic component near and below the ankle and intermediate composition above, has proved exceedingly challenging to understand theoretically, without fine-tuning. We propose a mechanism whereby photo-disintegration of ultrahigh energy nuclei in the region surrounding a UHECR accelerator accounts for the observed spectrum and inferred composition at Earth. For suitable source conditions, the model reproduces the spectrum and the composition over the entire extragalactic cosmic ray energy range, i.e. above 10^17.5 eV. Predictions for the spectrum and flavors of neutrinos resulting from this process are also presented.

Citations

• Observation of the Suppression of the Flux of Cosmic Rays above4×1019 eV
• TeVγrays and neutrinos from photodisintegration of nuclei in Cygnus OB2
• Cosmic rays around 10 18 eV : Implications of contemporary measurements on the origin of the ankle feature
• On the propagation of the highest energy cosmic ray nuclei
• KASCADE measurements of energy spectra for elemental groups of cosmic rays: Results and open problems
• Ultra high energy cosmic rays: implications of Auger data for source spectra and chemical composition
• A depression before a bump in the highest energy cosmic ray spectrum
• Big-Bang Nucleosynthesis

Cited by

• Ultra-High-Energy Cosmic Rays
• Strange fireball as an explanation of the muon excess in Auger data