Constraints on the Correlation of IceCube Neutrinos with Tracers of Large-Scale Structure

TL;DR

This study investigates the correlation between IceCube astrophysical neutrinos and large-scale structure tracers, finding no significant correlation and constraining the contribution of galaxy-correlated sources to the neutrino flux.

Contribution

It provides the first cross-correlation analysis between IceCube neutrinos and infrared galaxy catalogs, constraining source evolution models and their contribution to the neutrino flux.

Findings

No significant correlation between neutrinos and galaxy catalog.

Less than 54% of neutrino flux is from galaxy-correlated sources.

Negative source evolution models are disfavored at 90% confidence.

Abstract

The IceCube Neutrino Observatory has observed extragalactic astrophysical neutrinos with an apparently isotropic distribution. Only a small fraction of the observed astrophysical neutrinos can be explained by known sources. Neutrino production is thought to occur in energetic environments that are ultimately powered by the gravitational collapse of dense regions of the large-scale mass distribution in the universe. Whatever their identity, neutrino sources likely trace this large-scale mass distribution. The clustering of neutrinos with a tracer of the large-scale structure may provide insight into the distribution of neutrino sources with respect to redshift and the identity of neutrino sources. We implement a two-point angular cross-correlation of the Northern sky track events with an infrared galaxy catalog derived from WISE and 2MASS source catalogs that trace the nearby large-scale structure. No statistically significant correlation is found between the neutrinos and this infrared galaxy catalog. We find that < ~54% of the diffuse muon neutrino flux can be attributed to sources correlated with the galaxy catalog with 90% confidence. Additionally, when assuming that the neutrino source comoving density evolves following a power-law in redshift, $dN_s/dV \propto (1+z)^{k}$, we find that sources with negative evolution, in particular k < -1.75, are disfavored at the 90% confidence level