Search for Galactic disk and halo components in the arrival directions of high-energy astrophysical neutrinos

Understand

Arrival directions of 40 neutrino events with energies >~100 TeV, observed by the IceCube experiment, are studied.

• Their distribution in the Galactic latitude and in the angular distance to the Galactic Center allow to search for the Milky-Way disk and halo-related components, respectively.
• No statistically significant evidence for the disk component is found, though even 100% disk origin of the flux is allowed at the 90% confidence level.
• Contrary, the Galactic Center-Anticenter dipole anisotropy, specific for dark-matter decays (annihilation) or for interactions of cosmic rays with the extended halo of circumgalactic gas, is clearly favoured over the isotropic distribution (the probability of a fluctuation of the isotropic signal is ~2%).