Evidence for the Galactic contribution to the IceCube astrophysical neutrino flux

TL;DR

This paper provides evidence that a significant portion of the IceCube astrophysical neutrino flux originates from the Milky Way galaxy, based on the distribution of detected events across Galactic latitudes.

Contribution

It demonstrates the Galactic contribution to the neutrino flux by analyzing the latitude distribution of high-energy events, showing inconsistency with an isotropic flux model.

Findings

Galactic latitude distribution shows excess at |b|<10°

Deficit at |b|>50°

Inconsistency with isotropic model at > 3 sigma

Abstract

We show that the Galactic latitude distribution of IceCube astrophysical neutrino events with energies above 100~TeV is inconsistent with the isotropic model of the astrophysical neutrino flux. Namely, the Galactic latitude distribution of the events shows an excess at low latitudes |b|<10 degrees and a deficit at high Galactic latitude |b|> 50 degrees. We use Monte-Carlo simulations to show that the inconsistency of the isotropic signal model with the data is at > 3 sigma level, after the account of trial factors related to the choice of the low-energy threshold and Galactic latitude binning in our analysis.