Cosmogenic neutrinos and gamma-rays and the redshift evolution of UHECR sources

TL;DR

This paper explores how secondary neutrinos and gamma rays produced by ultra-high-energy cosmic rays can reveal information about the evolution of their extragalactic sources across cosmic time.

Contribution

It demonstrates the potential of using cosmic rays, neutrinos, and gamma rays together to constrain the redshift evolution of UHECR sources.

Findings

Secondary neutrino and gamma-ray fluxes depend strongly on source evolution.

Multi-messenger observations can provide complementary insights into UHECR origins.

The study highlights the importance of cosmic background interactions in shaping observable fluxes.

Abstract

If ultra-high-energy cosmic rays (UHECRs) have extragalactic origins, as is widely assumed to be the case at least for the majority of cosmic rays with energies above a few EeV, secondary neutrinos and photons can be expected to be produced during the propagation of UHECRs through intergalactic space via interactions with cosmic background photons. The fluxes of such secondary particles are strongly dependent on the redshift evolution of the emissivity (number density times luminosity) of UHECR sources. We show how cosmic rays, neutrinos, and gamma rays can potentially provide complementary information about UHECR source evolution.