Gravitational clustering of cosmic relic neutrinos in the Milky Way

TL;DR

This paper introduces a reweighting technique in N-one-body simulations to efficiently evaluate how gravitational clustering affects cosmic relic neutrinos in the Milky Way, aiding future detection efforts.

Contribution

A novel reweighting method in N-one-body simulations that allows for flexible neutrino mass and distribution modeling in studying cosmic neutrino clustering.

Findings

Neutrino density contrast near Earth is proportional to the square of neutrino mass.

Reweighting technique enables efficient exploration of different neutrino parameters.

Results support the feasibility of detecting cosmic relic neutrinos based on clustering effects.

Abstract

The standard model of cosmology predicts the existence of cosmic neutrino background in the present Universe. To detect cosmic relic neutrinos in the vicinity of the Earth, it is necessary to evaluate the gravitational clustering effects on relic neutrinos in the Milky Way. Here we introduce a reweighting technique in the N-one-body simulation method, so that a single simulation can yield neutrino density profiles for different neutrino masses and phase space distributions. In light of current experimental results that favor small neutrino masses, the neutrino number density contrast around the Earth is found to be almost proportional to the square of neutrino mass. The density contrast-mass relation and the reweighting technique are useful for studying the phenomenology associated with the future detection of the cosmic neutrino background.