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arXiv 0907.3919astro-ph.CO
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关于宇宙学重子分数的可能变化

On Possible Variation in the Cosmological Baryon Fraction

Gilbert P. Holder, Kenneth M. Nollett, Alexander van Engelen

摘要:

以重子或暗物质形式存在的那部分物质可能具有重子-暗物质等曲率波动形式的空间波动。我们使用大爆炸核合成计算与观测到的轻元素丰度以及星系团气体分数,以约束重子分数的宇宙学变化。轻元素丰度限制空间变化小于26- 27%,而“放松”的星系团样本显示气体分数的空间变化小于8%。较大的空间变化可能会导致初级宇宙微波背景各向异性的差异屏蔽,导致波动的不对称性,并缓解与晕星7 Li丰度的一些紧张关系。在我们允许的范围内的波动可以导致“B模式”CMB偏振各向异性在一个不可忽略的水平。

英文摘要:

The fraction of matter that is in the form of baryons or dark matter could have spatial fluctuations in the form of baryon-dark matter isocurvature fluctuations. We use big bang nucleosynthesis calculations compared with observed light element abundances as well as galaxy cluster gas fractions to constrain cosmological variations in the baryon fraction. Light element abundances constrain spatial variations to be less than 26-27%, while a sample of "relaxed" galaxy clusters shows spatial variations in gas fractions less than 8%. Larger spatial variations could cause differential screening of the primary cosmic microwave background anisotropies, leading to asymmetries in the fluctuations and ease some tension with the halo-star 7Li abundance. Fluctuations within our allowed bounds can lead to "B-mode" CMB polarization anisotropies at a non-negligible level.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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