Cascade photons as test of protons in UHECR

2016/06/30 by V. Berezinsky, A. Z. Gazizov, A. Gazizov +1 · 3 citations
Physics and Astronomy · #Astrophysics and Cosmic Phenomena #Cascade #Neutrino Physics Research #Nuclear physics #Particle physics #Particle physics theoretical and experimental studies #Photon #Physics #Quantum mechanics #Test (biology) #astro-ph.HE

paper · pdf · doi:10.1016/j.astropartphys.2016.08.007

published as Astroparticle Physics, Volume 84, November 2016, Pages 52-61 · Version accepted for publication in Astroparticle Physics. Most recent neutrino flux limits by IceCube were included to the tables. 14 pages, 13 figures

arxiv created 2016/08/28 · openalex publication_date 2016/09/03 · arxiv updated 2016/12/26 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05

Abstract

An isotropic component of high energy γ-ray spectrum measured by Fermi LAT constrains the proton component of UHECR. The strongest restriction comes from the highest, (580-820) GeV, energy bin. One more constraint on the proton component is provided by the IceCube upper bound on ultrahigh energy cosmogenic neutrino flux. We study the influence of these restrictions on the source properties, such as evolution and distribution of sources, their energy spectrum and admixture of nuclei. We also study the sensitivity of restrictions to various Fermi LAT galactic foreground models (model B being less restrictive), to the choice of extragalactic background light model and to overall normalization of the energy spectrum. We claim that the γ-ray-cascade constraints are stronger than the neutrino ones, and that however many proton models are viable. The basic parameters of such models are relatively large γ_g and not very large z_max. The allowance for He⁴ admixture also relaxes the restrictions. However we foresee that future CTA measurements of γ-ray spectrum at E_γ≃ (600 - 800) GeV, as well as resolving of more individual γ-ray sources, may rule out the proton-dominated cosmic ray models.

Citations

• Statistics of Clustering of Ultrahigh Energy Cosmic Rays and the Number of Their Sources
• Constraints on the origin of ultra-high-energy cosmic rays from cosmogenic neutrinos and photons
• A dip in the UHECR spectrum and the transition from galactic to extragalactic cosmic rays
• Revealing the High-Redshift Star Formation Rate with Gamma-Ray Bursts
• Ultrahigh-energy neutrino fluxes and their constraints
• Neutrino Astronomy (Rapporteur Talk)

Cited by

• Strange fireball as an explanation of the muon excess in Auger data
• Cosmogenic photon and neutrino fluxes in the Auger era
• SimProp v2r4: Monte Carlo simulation code for UHECR propagation