Combined fit of spectrum and composition data as measured by the Pierre Auger Observatory

THE PIERRE AUGER COLLABORATION, INCLUYE S. MOLLERACH

JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS

IOP PUBLISHING LTD

Lugar: Londres; Año: 2017

1475-7516

We present a combined fit of a simple astrophysical model of UHECRsources to both the energy spectrum and mass composition data measuredby the Pierre Auger Observatory. The fit has been performed for energiesabove 5 ṡ 1018 eV, i.e. the region of the all-particlespectrum above the so-called "ankle" feature. The astrophysical model weadopted consists of identical sources uniformly distributed in acomoving volume, where nuclei are accelerated through arigidity-dependent mechanism. The fit results suggest sourcescharacterized by relatively low maximum injection energies, hard spectraand heavy chemical composition. We also show that uncertainties aboutphysical quantities relevant to UHECR propagation and shower developmenthave a non-negligible impact on the fit results.