Anisotropy in Cosmic-Ray Arrival Directions in the Southern Hemisphere with Six Years of Data from the IceCube Detector

Understand

The IceCube Neutrino Observatory has accumulated a total of 318 billion cosmic-ray induced muon events between May 2009 and May 2015.

• This data set was used for a detailed analysis of the cosmic-ray arrival direction anisotropy in the TeV to PeV energy range.
• The observed global anisotropy features large regions of relative excess and deficit, with amplitudes on the order of $10^{-3}$ up to about 100 TeV.
• A decomposition of the arrival direction distribution into spherical harmonics shows that most of the power is contained in the low-multipole ($\ell\leq 4$) moments.