TY - JOUR

T1 - An updated estimate of the cosmic radio background and implications for ultra-high-energy photon propagation

AU - Nitu, Iuliana-Camelia

AU - Bevins, Harry

AU - Bray, Justin

AU - Scaife, Anna

PY - 2021/3

Y1 - 2021/3

N2 - We present an updated estimate of the cosmic radio background (CRB) and the corresponding attenuation lengths for ultra-high energy photons. This new estimate provides associated uncertainties as a function of frequency derived from observational constraints on key physical parameters. We also present the expected variation in the spectrum of the CRB as a function of these parameters, as well as accounting for the expected variation in spectral index among the population of radio galaxies. The new estimate presented in this work shows better agreement with observational constraints from radio source-count measurements than previous calculations. In the energy regime where we expect cosmogenic photons dominantly attenuated by the CRB, our calculation of the attenuation length differs from previous estimates by a factor of up to 3, depending on energy and the specific model for comparison. These results imply a decrease in the expected number of cosmogenic photons with energies ~10^19 – 10^20 eV.

AB - We present an updated estimate of the cosmic radio background (CRB) and the corresponding attenuation lengths for ultra-high energy photons. This new estimate provides associated uncertainties as a function of frequency derived from observational constraints on key physical parameters. We also present the expected variation in the spectrum of the CRB as a function of these parameters, as well as accounting for the expected variation in spectral index among the population of radio galaxies. The new estimate presented in this work shows better agreement with observational constraints from radio source-count measurements than previous calculations. In the energy regime where we expect cosmogenic photons dominantly attenuated by the CRB, our calculation of the attenuation length differs from previous estimates by a factor of up to 3, depending on energy and the specific model for comparison. These results imply a decrease in the expected number of cosmogenic photons with energies ~10^19 – 10^20 eV.

U2 - 10.1016/j.astropartphys.2020.102532

DO - 10.1016/j.astropartphys.2020.102532

M3 - Article

VL - 126

JO - Astroparticle Physics

JF - Astroparticle Physics

SN - 0927-6505

IS - 102532

ER -