Neutrino clustering in the Milky Way

TL;DR

This paper reviews the potential clustering of cosmic neutrinos in the Milky Way and discusses how this affects the prospects of detecting the Cosmic Neutrino Background with upcoming experiments.

Contribution

It provides a detailed computation of the local relic neutrino density considering neutrino mass and gravitational attraction, informing detection strategies.

Findings

Massive neutrinos can cluster around the Milky Way, increasing local density.

The local overdensity depends on minimal neutrino masses from oscillation data.

Prospects for detection with PTOLEMY-like experiments are realistically assessed.

Abstract

The Cosmic Neutrino Background is a prediction of the standard cosmological model, but it has been never observed directly. In the experiments with the aim of detecting relic CNB neutrinos, currently under development, the expected event rate depends on the local density of relic neutrinos. Since massive neutrinos can be attracted by the gravitational potential of our galaxy and cluster around it, a local overdensity of cosmic neutrinos should exist. Considering the minimal masses guaranteed by neutrino oscillations, we review the computation of the local density of relic neutrinos and we present realistic prospects for a PTOLEMY-like experiment.