Tomographic constraints on the high-energy cosmic neutrino emission rate

TL;DR

This paper uses cross-correlation of IceCube neutrino data with galaxy maps to constrain the redshift evolution of high-energy cosmic neutrino emission, providing upper bounds and testing source models.

Contribution

It introduces a novel method of constraining neutrino emissivity evolution by cross-correlating neutrino data with large-scale structure maps, including non-parametric reconstruction.

Findings

No significant correlation detected, strongest deviation is 1.9 sigma.

Upper bounds set on neutrino emission rate as a function of redshift.

Method offers a new way to test extragalactic neutrino source models.

Abstract

Despite growing efforts to find the sources of high energy neutrinos measured by IceCube, the bulk of the neutrinos remain with unknown origins. We aim to constrain the emissivity of cosmic high-energy neutrinos from extragalactic sources through their correlation with the large-scale structure. We use cross-correlations between the IceCube 10-year dataset and tomographic maps of the galaxy overdensity to place constraints on the bias-weighted high-energy neutrino emissivity out to redshift $z\sim3$. We test two different models to describe the evolution of neutrino emissivity with redshift, a power law model $\propto (1+z)^a$, and a model tracking the star formation history, assuming a simple power law model for the energy injection spectrum. We also consider a non-parametric reconstruction of the astrophysical neutrino emissivity as a function of redshift. We do not find any significant correlation, with our strongest results corresponding to a $1.9 \sigma$ deviation with respect to a model with zero signal. We use our measurements to place upper bounds on the bias-weighted astrophysical high-energy neutrino emission rate as a function of redshift for different source models. This analysis provides a new probe to test extragalactic neutrino source models. With future neutrino and galaxy datasets we expect the constraining and detection power of this type of analysis analysis to increase.