Few-degree anisotropies in the cosmic-ray flux observed by the ARGO-YBJ experiment

摘要

The ARGO-YBJ experiment is a full coverage EAS array sensitive to gamma rays and cosmic rays with energythreshold few hundreds GeV. We analyzed the data taken since November 2007 looking for few-degree anisotropies inthe arrival directions of cosmic rays. We found several regions with significant excesses (up to 17 s.d.), whose relativeintensity with respect to the isotropic flux extends up to 103 . The maximum excess occurs for proton energies of 10TeV, suggesting the presence of unknown features of the magnetic fields the charged cosmic rays propagate through, aswell as potential contributions of nearby sources to the total flux of cosmic rays.