The Primordial Abundance of Deuterium: Ionization correction
The Primordial Abundance of Deuterium: Ionization correction
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氘的原始丰度：电离校正
DOI：
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
U. Cambridge
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文献类型：
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作者：
R. Cooke;M. Pettini;U. California;Santa Cruz;I. O. Astronomy;U. Cambridge
我们使用一套详细的光电离模拟来确定低金属丰度阻尼莱曼-α (DLA) 和亚 DLA 系统中氘和氢的相对电离。我们将贫金属 DLA 建模为与宿主暗物质晕处于压力平衡状态的气体云，暴露于红移 z~3 处的星系和类星体的 Haardt & Madau (2012) 背景辐射下。我们的结果表明，氘电离校正与 H I 柱密度和最常见金属的连续离子阶段的比率相关。 N(N II) / N(N I) 柱密度比提供了最可靠的校正因子，基本上独立于气体几何形状、H I 柱密度和辐射场。我们提供了一系列方便的拟合公式来计算基于可观测量的氘电离校正。对于贫金属 DLA，电离校正通常不超过 0.1%，这远低于当前的测量精度 (2%)。然而，当获得更大的 D/H 测量样本时，可能需要应用氘电离校正。
We determine the relative ionization of deuterium and hydrogen in low metallicity damped Lyman-alpha (DLA) and sub-DLA systems using a detailed suite of photoionization simulations. We model metal-poor DLAs as clouds of gas in pressure equilibrium with a host dark matter halo, exposed to the Haardt & Madau (2012) background radiation of galaxies and quasars at redshift z~3. Our results indicate that the deuterium ionization correction correlates with the H I column density and the ratio of successive ion stages of the most commonly observed metals. The N(N II) / N(N I) column density ratio provides the most reliable correction factor, being essentially independent of the gas geometry, H I column density, and the radiation field. We provide a series of convenient fitting formulae to calculate the deuterium ionization correction based on observable quantities. The ionization correction typically does not exceed 0.1 per cent for metal-poor DLAs, which is comfortably below the current measurement precision (2 per cent). However, the deuterium ionization correction may need to be applied when a larger sample of D/H measurements becomes available.