论文标题
氧气增强的极为金属贫困的DLA：第一批恒星的路标？
Oxygen-enhanced extremely metal-poor DLAs: A signpost of the first stars?
论文作者
论文摘要
我们介绍了两个近原始阻尼$α$系统（DLA）的精确确定，以评估[o/h] <-3的[o/fe]比率的性质（即太阳金属性的<1/1000）。先前的观察结果表明，当-3 <[fe/h] <-2时，[o/fe]比与恒定值[o/fe]〜+0.4一致，但是当[fe/h] <-3 <-3时，该比率可能会增加。在本文中，我们通过在目前已知的两个最贫穷的DLA中报告新的高精度[O/Fe]丰度来测试这张照片。对于这两个Z〜3近原始气云，我们得出[O/Fe] = +0.50 +/- 0.10的值，[O/Fe] = +0.62 +/- 0.05。这些结果增强了与[Fe/H]> -3的DLA相比，最贫穷的DLA的[O/Fe]丰度升高。我们将观察到的后一个系统的丰度模式与人口III超新星（SNE）的核合成产量进行了比较，并发现富集可以由A（19-25）M $ _ {\ odot} $ sups III III SN（0.9-2.4）（0.9-2.4）$ \ times times 10^^51} $ explosion进行了描述。这些高精度测量值展示了[O/Fe]在大多数金属贫困环境中的行为。新系统中未来的高精度测量结果将有助于对[O/Fe]和[Fe/H]之间的关系进行牢固的检测。这些数据将揭示我们是否目睹了人口III星的富集的化学签名，并使我们能够排除人口II星的污染。
We present precise abundance determinations of two near-pristine damped Ly$α$ systems (DLAs) to assess the nature of the [O/Fe] ratio at [Fe/H] < -3 (i.e. <1/1000 of the solar metallicity). Prior observations indicate that the [O/Fe] ratio is consistent with a constant value, [O/Fe] ~ +0.4, when -3 < [Fe/H] < -2, but this ratio may increase when [Fe/H] < -3. In this paper, we test this picture by reporting new, high-precision [O/Fe] abundances in two of the most metal-poor DLAs currently known. We derive values of [O/Fe] = +0.50 +/- 0.10 and [O/Fe] = +0.62 +/- 0.05 for these two z ~ 3 near-pristine gas clouds. These results strengthen the idea that the [O/Fe] abundances of the most metal-poor DLAs are elevated compared to DLAs with [Fe/H] > -3. We compare the observed abundance pattern of the latter system to the nucleosynthetic yields of Population III supernovae (SNe), and find that the enrichment can be described by a (19-25) M$_{\odot}$ Population III SN that underwent a (0.9-2.4)$\times 10^{51}$ erg explosion. These high-precision measurements showcase the behaviour of [O/Fe] in the most metal-poor environments. Future high-precision measurements in new systems will contribute to a firm detection of the relationship between [O/Fe] and [Fe/H]. These data will reveal whether we are witnessing a chemical signature of enrichment from Population III stars and allow us to rule out contamination from Population II stars.
