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

Arrival directions of 40 neutrino events with energies ${\gtrsim}$ 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 ${\sim}$ 2 %).