Subaru/HSC identifications of protocluster candidates at z~6-7: Implications for cosmic reionization
Subaru/HSC identifications of protocluster candidates at z~6-7: Implications for cosmic reionization
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Subaru/HSC 对 z~6-7 候选原星系团的识别：对宇宙再电离的影响
DOI：
10.1017/s1743921319002795
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Ito
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文献类型：
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作者：
Higuchi Ryo;Ouchi Masami;Ono Yoshiaki;Shibuya Takatoshi;Toshikawa Jun;Harikane Yuichi;Kojima Takashi;Chiang Yi-Kuan;Egami Eiichi;Kashikawa Nobunari;Overzier Roderik;Konno Akira;Inoue Akio K.;Hasegawa Kenji;Fujimoto Seiji;Goto Tomotsugu;Ishikawa Shogo;Ito
我们报告了 14 和 19 deg2 区域中 z = 5.7 和 6.6 的 14 个和 28 个原星团候选者，分别是从通过 Subaru/Hyper Suprime-Cam (HSC) 深度图像光度识别的 2,230 个 Lyα 发射器 (LAE) 中选出的。 42 个候选原星团中的 6 个包含至少 1 个经光谱确认的 LAE，其红移高达 z = 6.574。通过与再现具有再电离效应的LAE的宇宙学Lyα辐射传输（RT）模型的比较，我们发现这些原星团候选者中超过一半可能是当今质量为≳1014M⊙的星团的前身。我们还研究了 LAE 超密度和 Lya 静止框架等效宽度 (EW) 之间的相关性，因为宇宙学 Lyα RT 模型表明，由于星系超密度周围电离气泡的存在，缓解了 Lyα 发射从部分中性的星际介质中逃逸，EW-超密度关系的斜率向宇宙再电离 (EoR) 时代变陡。现有的 HSC 数据表明，EW-超密度相关性的斜率不会从再电离后 z = 5.7 演化到 EoR z = 6.6，超出中等大的统计误差。
We report fourteen and twenty-eight protocluster candidates at z = 5.7 and 6.6 over 14 and 19 deg2 areas, respectively, selected from 2,230 Lyα emitters (LAEs) photometrically identified with Subaru/Hyper Suprime-Cam (HSC) deep images. Six out of the 42 protocluster candidates include at least 1 spectroscopically confirmed LAEs at redshifts up to z = 6.574. By the comparisons with the cosmological Lyα radiative transfer (RT) model reproducing LAEs with the reionization effects, we find that more than a half of these protocluster candidates might be progenitors of the present-day clusters with a mass of ≳ 1014M⊙. We also investigate the correlation between LAE overdensity and Lya rest-frame equivalent width (EW), because the cosmological Lyα RT model suggests that a slope of EW-overdensity relation is steepened towards the epoch of cosmic reionization (EoR), due to the existence of the ionized bubbles around galaxy overdensities easing the escape of Lyα emission from the partly neutral intergalactic medium. The available HSC data suggest that the slope of the EW-overdensity correlation does not evolve from the post-reionization epoch z = 5.7 to the EoR z = 6.6 beyond the moderately large statistical errors.