UCL Discovery
UCL home » Library Services » Electronic resources » UCL Discovery

Ultra-High-energy Cosmic Rays from beyond the Greisen-Zatsepin-Kuz'min Horizon

Owen, ER; Han, Q; Wu, K; Yap, YXJ; Surajbali, P; (2021) Ultra-High-energy Cosmic Rays from beyond the Greisen-Zatsepin-Kuz'min Horizon. Astrophysical Journal , 922 (1) , Article 32. 10.3847/1538-4357/ac185c. Green open access

[thumbnail of Owen_2021_ApJ_922_32.pdf]
Preview
Text
Owen_2021_ApJ_922_32.pdf - Published Version

Download (1MB) | Preview

Abstract

Ultra-high-energy (UHE) cosmic rays (CRs) of energies ∼(1018–1020) eV, accelerated in violent astrophysical environments, interact with cosmic background radiation fields via photo-hadronic processes, leading to strong attenuation. Typically, the Universe would become "opaque" to UHE CRs after several tens of megaparsecs, setting the boundary of the Greisen–Zatsepin–Kuz'min (GZK) horizon. In this work, we investigate the contribution of sources beyond the conventional GZK horizon to the UHE CR flux observed on Earth, when photospallation of the heavy nuclear CRs is taken into account. We demonstrate that this contribution is substantial, despite the strong attenuation of UHE CRs. A significant consequence is the emergence of an isotropic background component in the observed flux of UHE CRs, coexisting with the anisotropic foreground component that is associated with nearby sources. Multi-particle CR horizons, which evolve over redshift, are determined by the CR nuclear composition. Thus, they are dependent on the source populations and source evolutionary histories.

Type: Article
Title: Ultra-High-energy Cosmic Rays from beyond the Greisen-Zatsepin-Kuz'min Horizon
Open access status: An open access version is available from UCL Discovery
DOI: 10.3847/1538-4357/ac185c
Publisher version: https://doi.org/10.3847/1538-4357/ac185c
Language: English
Additional information: This version is the version of record. For information on re-use, please refer to the publisher’s terms and conditions.
Keywords: Science & Technology, Physical Sciences, Astronomy & Astrophysics, EXTRAGALACTIC BACKGROUND LIGHT, ACTIVE GALACTIC NUCLEI, ANALYTIC CALCULATIONS, LUMINOSITY FUNCTION, PAIR PRODUCTION, POINT-SOURCE, GAMMA-RAYS, SPECTRUM, PARTICLES, ORIGIN, Cosmic ray sources; Ultra-high-energy cosmic radiation; Secondary cosmic rays; Astronomical radiation sources; Extragalactic astronomy
UCL classification: UCL
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Space and Climate Physics
URI: https://discovery.ucl.ac.uk/id/eprint/10139356
Downloads since deposit
55Downloads
Download activity - last month
Download activity - last 12 months
Downloads by country - last 12 months

Archive Staff Only

View Item View Item