1. Subaru/HSC identifications of protocluster candidates at z ∼ 6–7: Implications for cosmic reionization
- Author
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Tomotsugu Goto, Masayuki Tanaka, Nobunari Kashikawa, Kei Ito, Seiji Fujimoto, Akira Konno, Eiichi Egami, Yuichi Harikane, Roderik Overzier, Akio K. Inoue, Takatoshi Shibuya, Shogo Ishikawa, Jun Toshikawa, Yutaka Komiyama, Ryo Higuchi, Yi-Kuan Chiang, Masami Ouchi, Yoshiaki Ono, Kenji Hasegawa, and Takashi Kojima
- Subjects
Physics ,COSMIC cancer database ,010308 nuclear & particles physics ,Space and Planetary Science ,0103 physical sciences ,Astronomy ,Astronomy and Astrophysics ,010303 astronomy & astrophysics ,01 natural sciences ,Reionization - Abstract
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.
- Published
- 2019