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arXiv 0811.1216astro-ph
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理论HeI发射率的不确定性：HII区域、原始Absorption和宇宙学Absorption

Uncertainties in Theoretical HeI Emissivities: HII Regions, Primordial Abundance, and Cosmological Recombination

R. L. Porter, G. J. Ferland, K. B. MacAdam, P. J. Storey

备注：
5 pages, 3 figures, accepted to MNRAS Letters
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摘要：

最近在天文学和宇宙学方面的一些工作都依赖于理论上的He I发射率，但我们知道没有努力量化原子数据中的不确定性。我们分析和分配不确定性的所有相关的原子数据，进行蒙特卡罗分析，并报告标准偏差的线发射率。我们考虑两组错误，我们称之为“乐观”和“悲观”。“我们还考虑了三种不同的条件，对应于原型银河系和河外H II区域以及宇宙重组的时代。在河外H II的情况下，我们得到的误差是可比的，或更大的误差在最近的一些$Y_p$计算，包括来自CMB的观测。我们证明了系统的原始丰度计算的影响，这种影响不能通过观察大量的对象减少。在宇宙学复合的情况下，误差与最近计算中考虑的许多效应相当。

英文摘要：

A number of recent works in astronomy and cosmology have relied upon theoretical He I emissivities, but we know of no effort to quantify the uncertainties in the atomic data. We analyze and assign uncertainties to all relevant atomic data, perform Monte Carlo analyses, and report standard deviations in the line emissivities. We consider two sets of errors, which we call "optimistic" and "pessimistic." We also consider three different conditions, corresponding to prototypical Galactic and extragalactic H II regions and the epoch of cosmological recombination. In the extragalactic H II case, the errors we obtain are comparable to or larger than the errors in some recent $Y_p$ calculations, including those derived from CMB observations. We demonstrate a systematic effect on primordial abundance calculations; this effect cannot be reduced by observing a large number of objects. In the cosmological recombination case, the errors are comparable to many of the effects considered in recent calculations.

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