Evolution of the cosmic-ray anisotropy above 1014 eV

M. Aglietta, V. V. Alekseenko, B. Alessandro, P. Antonioli, F. Arneodo, L. Bergamasco, M. Bertaina, R. Bonino, A. Castellina, A. Chiavassa, B. D'Ettorre Piazzoli, G. Di Sciascio, W. Fulgione, P. Galeotti, P. L. Ghia, M. Iacovacci, G. Mannocchi, C. Morello, G. Navarra, O. SaavedraA. Stamerra, G. C. Trinchero, S. Valchierotti, P. Vallania, S. Vernetto, C. Vigorito

Research output: Contribution to journalArticlepeer-review


The amplitude and phase of the cosmic-ray anisotropy are well established experimentally between 1011 eV and 1014 eV. The study of their evolution in the energy region 1014-1016 eV can provide a significant tool for the understanding of the steepening ("knee") of the primary spectrum. In this Letter, we extend the EAS-TOP measurement performed at E 0 1014 eV to higher energies by using the full data set (eight years of data taking). Results derived at about 1014 and 4 × 1014 eV are compared and discussed. Hints of increasing amplitude and change of phase above 10 14 eV are reported. The significance of the observation for the understanding of cosmic-ray propagation is discussed.

Original languageEnglish (US)
Pages (from-to)L130-L133
JournalAstrophysical Journal
Issue number2
StatePublished - 2009


  • Cosmic rays
  • Diffusion

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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