The amplitude and phase of the cosmic-ray anisotropy are well established experimentally between 10(11) eV and 10(14) eV. The study of their evolution in the energy region 10(14)-10(16) 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 approximate to 10(14) eV to higher energies by using the full data set ( eight years of data taking). Results derived at about 10(14) and 4 x 10(14) 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.
Evolution of the Cosmic-Ray anisotropy above 10(14) eV
BERGAMASCO, Laura Maria;BERTAINA, Mario Edoardo;BONINO, Raffaella;CHIAVASSA, Andrea;GALEOTTI, Piero;NAVARRA, Gianni Maria;SAAVEDRA, Oscar;VIGORITO, Carlo Francesco
2009-01-01
Abstract
The amplitude and phase of the cosmic-ray anisotropy are well established experimentally between 10(11) eV and 10(14) eV. The study of their evolution in the energy region 10(14)-10(16) 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 approximate to 10(14) eV to higher energies by using the full data set ( eight years of data taking). Results derived at about 10(14) and 4 x 10(14) 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.File | Dimensione | Formato | |
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