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

TL;DR

This study analyzes high-energy neutrino arrival directions from IceCube to search for Galactic disk and halo signals, finding no significant disk evidence but indicating a possible Galactic Center-Anticenter anisotropy.

Contribution

It provides the first search for Galactic disk and halo components in high-energy neutrino arrival directions using IceCube data, highlighting a potential anisotropy related to the Galactic Center.

Findings

No significant disk component detected.

100% disk origin still compatible within 90% confidence.

Galactic Center-Anticenter dipole anisotropy favored over isotropy.

Abstract

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%).