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The origin of the ankle in the UHECR spectrum, and of the extragalactic protons below it

Aug 4, 2015, 3:45 PM
World Forum Theater (World Forum)

World Forum Theater

World Forum

Churchillplein 10 2517 JW Den Haag The Netherlands
Oral contribution CR-TH Parallel CR17 EAS spec


Prof. Glennys Farrar (New York University)


The sharp change in slope of the ultra-high energy cosmic ray 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. We propose a mechanism whereby photo-disintegration of ultra-high energy nuclei in the region surrounding a UHECR accelerator naturally accounts for the observed spectrum and inferred composition at Earth. We discuss the conditions required to reproduce the spectrum above 10^17.5 eV and the composition, which -- in our model -- consists below the ankle of extragalactic protons and the high energy tail of Galactic Cosmic Rays, and above the ankle of surviving nuclei from the extended source. Predictions for the spectrum and flavors of neutrinos resulting from this process will be presented, and also implications for candidate sources.
Collaboration -- not specified --
Registration number following "ICRC2015-I/" 388

Primary author

Prof. Glennys Farrar (New York University)


Prof. Luis Anchordoqui (Lehman College and CUNY) Dr Michael Unger (NYU and KIT)

Presentation materials