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

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