Document Type
Article
Publication Date
8-4-2008
Abstract
The energy spectrum of cosmic rays above 2.5×1018eV, derived from 20000 events recorded at the Pierre Auger Observatory, is described. The spectral index γ of the particle flux, JE-γ, at energies between 4×1018eV and 4×1019eV is 2.69±0.02(stat)±0.06(syst), steepening to 4.2±0.4(stat)±0.06(syst) at higher energies. The hypothesis of a single power law is rejected with a significance greater than 6 standard deviations. The data are consistent with the prediction by Greisen and by Zatsepin and Kuz'min. © 2008 The American Physical Society.
Publication Source (Journal or Book title)
Physical Review Letters
Recommended Citation
Abraham, J., Abreu, P., Aglietta, M., Aguirre, C., Allard, D., Allekotte, I., Allen, J., Allison, P., Alvarez-Muñiz, J., Ambrosio, M., Anchordoqui, L., Andringa, S., Anzalone, A., Aramo, C., Argirò, S., Arisaka, K., Armengaud, E., Arneodo, F., Arqueros, F., Asch, T., Asorey, H., Assis, P., Atulugama, B., Aublin, J., Ave, M., Avila, G., Bäcker, T., Badagnani, D., Barbosa, A., Barnhill, D., Barroso, S., Baughman, B., & Bauleo, P. (2008). Observation of the suppression of the flux of cosmic rays above 4×1019eV. Physical Review Letters, 101 (6) https://doi.org/10.1103/PhysRevLett.101.061101