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Ultrahigh-energy cosmogenic neutrino emissions in the high-redshift universe

Shigeru Yoshida* and Maximilian Meier†

  • International Center for Hadron Astrophysics, Chiba University, Chiba 263-8522, Japan

  • *Contact author: syoshida@hepburn.s.chiba-u.ac.jp
  • †Contact author: maximilian.meier@icecube.wisc.edu
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Phys. Rev. D 114, L041302 – Published 11 August, 2026

DOI: https://doi.org/10.1103/ljz7-phzv

Abstract

The James Webb Space Telescope (JWST) revealed a large population of active galactic nuclei (AGN) with redshifts greater than five. We show that if they emit ultrahigh-energy protons with energies up to ≲1019  eV, the cosmogenic neutrino production in the high-redshift CMB field yields a neutrino flux with a bump at around 50 PeV. This flux is potentially consistent with the current neutrino intensity estimate by the IceCube Neutrino Observatory within the parameter space allowed from the AGN luminosity and number density estimates by JWST. Future neutrino observations that confirm the 50-PeV bump and constrain the small-scale anisotropy will infer ultrahigh-energy cosmic-ray emissions in the early Universe.

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Outline

Information

Phys. Rev. D 114, L041302– Published 11 August, 2026
  • Received 15 April 2026
  • Accepted 20 July 2026
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