Tomographic constraints on the high-energy cosmic neutrino emission rate

ABSTRACT Despite growing efforts to find the sources of high-energy neutrinos measured by IceCube, the bulk of the neutrinos remain with unknown origins. In this work, 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 data set and tomographic maps of the galaxy overdensity to place constraints on the bias-weighted high-energy neutrino emissivity out to redshift $z\sim 3$. 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 data sets, we expect the constraining and detection power of this type of analysis to increase.