Abstract 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.

中文翻译：

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对宇宙无线电背景的最新估计及其对超高能光子传播的影响

摘要 我们提出了宇宙射电背景 (CRB) 的最新估计值以及超高能光子的相应衰减长度。这个新的估计提供了相关的不确定性，作为频率的函数，从关键物理参数的观测约束中得出。我们还将 CRB 光谱的预期变化作为这些参数的函数，并解释了射电星系群之间光谱指数的预期变化。与之前的计算相比，这项工作中提出的新估计更符合无线电源计数测量的观测约束。在我们预计宇宙光子主要被 CRB 衰减的能量范围内，我们对衰减长度的计算与之前的估计相差高达 3 倍，视能量和具体型号进行比较。这些结果意味着能量约为 10 19 – 10 20 eV 的宇宙光子的预期数量减少。