Predictions for the flux of high-energy cosmogenic neutrinos and the influence of the extragalactic magnetic field

TL;DR

This paper models the flux of high-energy cosmogenic neutrinos using detailed simulations, highlighting the significant impact of extragalactic magnetic fields on their detectability, which informs future neutrino observatory designs.

Contribution

It provides the first comprehensive four-dimensional simulation-based predictions of cosmogenic neutrino flux considering magnetic field effects.

Findings

Predicted neutrino flux aligns with current experimental upper limits.

Extragalactic magnetic fields significantly influence neutrino flux levels.

Results aid in designing future neutrino detectors for high-energy astrophysics.

Abstract

Cosmogenic neutrinos originate from interactions of cosmic rays propagating through the universe with cosmic background photons. Since both high-energy cosmic rays and cosmic background photons exist, the existence of high-energy cosmogenic neutrinos is almost certain. However, their flux has not been measured so far. Therefore, we calculated the flux of high-energy cosmogenic neutrinos arriving at the Earth on the basis of elaborate four-dimensional simulations that take into account three spatial degrees of freedom and the cosmological time-evolution of the universe. Our predictions for this neutrino flux are consistent with the recent upper limits obtained from large-scale cosmic-ray experiments. We also show that the extragalactic magnetic field has a strong influence on the neutrino flux. The results of this work are important for the design of future neutrino observatories, since they allow to assess the detector volume that is necessary to detect high-energy cosmogenic neutrinos in the near future. An observation of such neutrinos would push multimessenger astronomy to hitherto unachieved energy scales.