Constraining the Neutral Fraction of Hydrogen in the IGM at Redshift 7.5
Constraining the Neutral Fraction of Hydrogen in the IGM at Redshift 7.5
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DOI：
10.3847/1538-4357/ab1de7
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发表时间：
2019-01
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影响因子：
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通讯作者：
A. Hoag;M. Bradavc;K. Huang;C. Mason;T. Treu;K. Schmidt;M. Trenti;V. Strait;B. Lemaux;E. Finney;Maia Paddock
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作者：
A. Hoag;M. Bradavc;K. Huang;C. Mason;T. Treu;K. Schmidt;M. Trenti;V. Strait;B. Lemaux;E. Finney;Maia Paddock
利用Keck/多目标光谱仪对12个有效星系团透镜后的暗Lyman break星系进行了大规模的光谱观测。引力透镜使我们能够探测更丰富的微弱星系人口敏感的Lyα等效宽度限制。在活动期间，我们瞄准了70个具有MOSFIRE Y波段的LBG候选者，通过光度测量选择以覆盖其中两个星系中的7 - 5发射线范围内的Lyα，并发现它们可能是z = 7.148 ± 0.001和z = 7.161 ± 0.001的Lyα。我们提出了新的透镜模型的四个星系团，使用我们以前发表的透镜模型的其余集群，以确定源星系的放大系数。使用贝叶斯框架，采用大规模的再电离模拟的星系际介质（IGM），以及星际介质和环星系介质的现实属性，我们推断体积平均中性氢分数，在IGM再电离过程中是在z = 7.6 ± 0.6。我们的结果是一致的后期和快速再电离的普朗克推断的情况。
We present a large spectroscopic campaign with Keck/Multi-Object Spectrometer for InfraRed Exploration (MOSFIRE) targeting Lyα emission (Lyα) from intrinsically faint Lyman-break galaxies (LBGs) behind 12 efficient galaxy cluster lenses. Gravitational lensing allows us to probe the more abundant faint galaxy population to sensitive Lyα equivalent-width limits. During the campaign, we targeted 70 LBG candidates with the MOSFIRE Y band, selected photometrically to cover Lyα over the range 7 5 emission lines in two of these galaxies and find that they are likely Lyα at z = 7.148 ± 0.001 and z = 7.161 ± 0.001. We present new lens models for four of the galaxy clusters, using our previously published lens models for the remaining clusters to determine the magnification factors for the source galaxies. Using a Bayesian framework that employs large-scale reionization simulations of the intergalactic medium (IGM) as well as realistic properties of the interstellar medium and circumgalactic medium, we infer the volume-averaged neutral hydrogen fraction, , in the IGM during reionization to be at z = 7.6 ± 0.6. Our result is consistent with a late and rapid reionization scenario inferred by Planck.