Ultra high energy cosmic rays: implications of Auger data for source spectra and chemical composition
By R. Aloisio, V. Berezinsky, P. Blasi. 2013
142 citations recorded by the source corpus.
We use a kinetic-equation approach to describe the propagation of ultra high energy cosmic ray protons and nuclei and calculate the expected spectra and mass composition at the Earth for different assumptions on the source injection spectra and chemical abundances. When compared with the spectrum, the elongation rate Xmax(E) and dispersion σ(Xmax) as observed with the Pierre Auger Observatory, several important consequences can be drawn: a) the injection spectra of nuclei must be very hard, ∼ E-γ with γ∼ 1- 1.6; b) the maximum energy of nuclei of charge Z in the sources must be ∼ 5Z× 1018 eV, thereby not requiring acceleration to extremely high energies; c) the fit to the Auger spectrum can be obtained only at the price of adding an ad hoc light extragalactic component with a steep injection spectrum ∼ E-2.7). In this sense, at the ankle EA≈ 5× 1018 eV) all the components are of extragalactic origin, thereby suggesting that the transition from Galactic to extragalactic cosmic rays occurs below the ankle. Interestingly, the additional light extragalactic component postulated above compares well, in terms of spectrum and normalization, with the one recently measured by KASCADE-Grande.
Subfields: Nuclear and High Energy Physics
View Paper: https://www.semanticscholar.org/paper/df0425950b20378872822b057414549838d0fbf2
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In Nuclear and High Energy Physics
Citations in the corpus
- Combined fit of spectrum and composition data as measured by the Pierre Auger Observatory (2016, methodology): “The essential features of such a model have been discussed elsewhere [19, 20] and, using a similar approach to that of this work, in [21], the general features being a low maximum rigidity around log10(Rcut/V) = 18.”
- Cosmic-ray energy spectrum and composition up to the ankle - the case for a second Galactic component (2016, background): “It has been shown that the observed spectrum and composition at the highest energies can be explained by a mixed-composition extra-galactic source spectrum with progressive cuto↵s at ⇠Z ⇥ 5⇥ 109 GeV, where Z is the nuclear charge (Aloisio et al. 2014).”