A Significantly Neutral Intergalactic Medium Around the Luminous z = 7 Quasar J0252–0503
A Significantly Neutral Intergalactic Medium Around the Luminous z = 7 Quasar J0252–0503
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DOI：
10.3847/1538-4357/ab8c45
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发表时间：
2020-04
期刊：
影响因子：
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通讯作者：
Feige Wang;F. Davies;Jinyi Yang;J. Hennawi;Xiaohui Fan;A. Barth;Linhua Jiang;Xue-bing Wu
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文献类型：
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作者：
Feige Wang;F. Davies;Jinyi Yang;J. Hennawi;Xiaohui Fan;A. Barth;Linhua Jiang;Xue-bing Wu
发光z≥7的类星体提供了超大质量黑洞（SMBHs）和星系际介质（IGM）在再电离时代（EoR）演化的直接探测。在一个单一的EoR类星体光谱中，可以检测到由中性氢在IGM中印记的Lyα阻尼翼吸收，从而可以测量IGM中性部分朝向该视线。然而，在以往的研究中，只在两个z >7类星体中发现了阻尼翼的特征。本文利用Keck/近红外梯队光谱仪和Gemini/GMOS获得了z = 7.00类星体DES J025216.64-050331.8的高质量光学和近红外光谱。通过Mg ii单历元维里方法，我们发现它拥有一个以λEdd = 0.7±0.1的Eddington比率吸积的SMBH，与其他发光的z ~ 7类星体的值一致。此外，Lyα区表现出较强的阻尼翼吸收特征。类星体光谱中缺乏相关的金属吸收表明这种吸收是由中性IGM印记的。使用Davies等人开发的最先进的模型，我们在类星体寿命的边缘计算时，在z = 7的68%（95%）置信区间内测量了体积平均中性氢分数。这是迄今为止使用再电离时代的类星体光谱测量到的最高的IGM中性分数。
Luminous z ≥ 7 quasars provide direct probes of the evolution of supermassive black holes (SMBHs) and the intergalactic medium (IGM) during the epoch of reionization (EoR). The Lyα damping wing absorption imprinted by neutral hydrogen in the IGM can be detected in a single EoR quasar spectrum, allowing the measurement of the IGM neutral fraction toward that line of sight. However, damping wing features have only been detected in two z > 7 quasars in previous studies. In this paper, we present new high-quality optical and near-infrared spectroscopy of the z = 7.00 quasar DES J025216.64–050331.8 obtained with Keck/Near-Infrared Echellette Spectrometer and Gemini/GMOS. By using the Mg ii single-epoch virial method, we find that it hosts a SMBH accreting at an Eddington ratio of λEdd = 0.7 ± 0.1, consistent with the values seen in other luminous z ∼ 7 quasars. Furthermore, the Lyα region of the spectrum exhibits a strong damping wing absorption feature. The lack of associated metal absorption in the quasar spectrum indicates that this absorption is imprinted by a neutral IGM. Using a state-of-the-art model developed by Davies et al., we measure a volume-averaged neutral hydrogen fraction at z = 7 of within 68% (95%) confidence intervals when marginalizing over quasar lifetimes of . This is the highest IGM neutral fraction yet measured using reionization-era quasar spectra.