The end of the cosmic ray spectrum

Veberič, D. and Auger, Pierre (2011) The end of the cosmic ray spectrum. Il nuovo cimento C, 34 (s1). pp. 85-92. ISSN 1826-9885

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Recent results from the Pierre Auger Observatory are presented, focusing on a measurement of the cosmic-ray energy spectrum above 1018 eV, cosmicray composition, and the anisotropy in the cosmic ray arrival directions. The flux of cosmic rays can be well described by a broken power law, with a flattening of the spectrum above 4×1018 eV and a softening of the spectrum beginning at about 3×1019 eV. The flux suppression at highest energies is consistent with the predictions of Greisen, and Zatsepin and Kuzmin. Longitudinal development of cosmic-ray air showers provides information on the mass of the primary particle. When compared to model predictions, our measurements of the mean and spread of the longitudinal position of the shower maximum are indicating a composition transition from light to heavier with increasing energy. For highest energies in our data-set we observe evidence for a correlation between the cosmic-ray arrival directions and the nearby extragalactic objects.

Item Type: Article
Uncontrolled Keywords: Cosmic rays ; Extensive air showers ; Energetic particles ; Cosmic-ray interactions
Subjects: 500 Scienze naturali e Matematica > 530 Fisica
Depositing User: Marina Spanti
Date Deposited: 14 Apr 2020 16:26
Last Modified: 14 Apr 2020 16:26

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