1999/08/04 by Jorg P. Rachen, J. P. Rachen, Rachen, Jorg P. +5
Physics and Astronomy · #Astrophysics (astro-ph) #Astrophysics and Cosmic Phenomena #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #Neutrino Physics Research #Particle physics theoretical and experimental studies #astro-ph #hep-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/9908031
12 pages LaTeX, texas.sty included, no figures. Comment presented at the 19th Texas Symposium, Paris, December 1998. Slightly corrected/updated after resubmission of astro-ph/9812398
arxiv created 1999/08/04 · openalex publication_date 1999/08/04 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
In a recent paper, Waxman and Bahcall (PRD 59, 023002) claimed that the present data on ultra-high energy cosmic rays imply a model-independent upper bound on extragalactic neutrino fluxes of 2*10-8 GeV cm-2 s-1 ster-1, independent of neutrino energy. Mannheim, Protheroe and Rachen (astro-ph/9812398) have repeated this calculation and confirmed the WB-bound, within a factor of 2, only at a very limited energy range of Eν∼ 10^(16-18) eV, while at other energies the neutrino flux is mainly limited by the extragalactic gamma ray background to a level about two orders of magnitude higher than the WB bound. In this paper we present a simple, (almost) no-math approach to the problem, and discuss under which astrophysical assumptions the WB-bound and the MPR-bound, respectively, apply. Then we discuss to which respect these assumptions apply to presently discussed models of extragalactic neutrino production. We note that, averaged over the observed luminosity function, blazars are sufficiently opaque to ultra-high energy neutrons that there is no conflict of the predicted neutrino fluxes with the cosmic ray data, and that these models are rather constrained by their contributions to the extragalactic gamma ray background. At present, no modifications are implied to the predicted neutrino events from these models in active or planned neutrino detectors.