Abstract

I explore the possibility of estimating an upper limit for the present-day iron abundance in the baryonic matter at which the gamma-ray background from the decay of \({}^{56}\)Ni synthesized in the Universe to date comes into conflict with the observed MeV gamma-ray background. I calculate the brightness of the gamma-ray background from SNe Ia and SNe II by taking into account the gamma-ray scattering and absorption in supernova ejecta. The model brightness of the gamma-ray background is shown to be consistent with the observed MeV gamma-ray background if the iron abundance in the baryonic matter is less than 15\({\%}\) of the solar one.

中文翻译：

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宇宙中铁的丰度

摘要

我探索了估计当前重子物质中铁丰度上限的可能性，在该上限下，迄今为止在宇宙中合成的\({}^{56}\) Ni衰变产生的伽马射线背景进入与观测到的 MeV 伽马射线背景相冲突。我通过考虑超新星喷射物中的伽马射线散射和吸收来计算超新星 Ia 和超新星 II 伽马射线背景的亮度。如果重子物质中的铁丰度小于太阳铁丰度的 15 \({\%}\)，则伽马射线背景的模型亮度与观测到的 MeV 伽马射线背景一致。