The energy spectrum of cosmic rays above 2.5x10^18eV, derived from 20,000 events recorded at the Pierre Auger Observatory, is described. The spectral index gamma of the flux, J ~ E^-gamma, at energies between 4x10^18eV and 4x10^19eV is 2.69+-0.02(stat)+-0.06(syst), steepening to 4.2+-0.4(stat)+-0.06(syst) at higher energies, consistent with the prediction by Greisen and by Zatsepin and Kuz'min.
Observation of the suppression of the flux of cosmic rays above 4x10^19eV / Guarino, Fausto; D'Urso, Domenico; M., Ambrosio; Aramo, Carla; DELLA SELVA, Angelo; Miele, Gennaro; Pisanti, Ofelia; Valore, Laura. - In: PHYSICAL REVIEW LETTERS. - ISSN 0031-9007. - STAMPA. - 101:(2008), pp. 061101-061108. [10.1103/PhysRevLett.101.061101]
Observation of the suppression of the flux of cosmic rays above 4x10^19eV
GUARINO, FAUSTO;D'URSO, DOMENICO;ARAMO, CARLA;DELLA SELVA, ANGELO;MIELE, GENNARO;PISANTI, OFELIA;VALORE, LAURA
2008
Abstract
The energy spectrum of cosmic rays above 2.5x10^18eV, derived from 20,000 events recorded at the Pierre Auger Observatory, is described. The spectral index gamma of the flux, J ~ E^-gamma, at energies between 4x10^18eV and 4x10^19eV is 2.69+-0.02(stat)+-0.06(syst), steepening to 4.2+-0.4(stat)+-0.06(syst) at higher energies, consistent with the prediction by Greisen and by Zatsepin and Kuz'min.| File | Dimensione | Formato | |
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Phys Rev Lett. 101 (2008) 061101.pdf
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