1. SILVERRUSH. VIII. Spectroscopic Identifications of Early Large-scale Structures with Protoclusters over 200 Mpc at z ∼ 6–7: Strong Associations of Dusty Star-forming Galaxies
- Author
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Harikane, Yuichi, Ouchi, Masami, Ono, Yoshiaki, Fujimoto, Seiji, Donevski, Darko, Shibuya, Takatoshi, Faisst, Andreas L, Goto, Tomotsugu, Hatsukade, Bunyo, Kashikawa, Nobunari, Kohno, Kotaro, Hashimoto, Takuya, Higuchi, Ryo, Inoue, Akio K, Lin, Yen-Ting, Martin, Crystal L, Overzier, Roderik, Smail, Ian, Toshikawa, Jun, Umehata, Hideki, Ao, Yiping, Chapman, Scott, Clements, David L, Im, Myungshin, Jing, Yipeng, Kawaguchi, Toshihiro, Lee, Chien-Hsiu, Lee, Minju M, Lin, Lihwai, Matsuoka, Yoshiki, Marinello, Murilo, Nagao, Tohru, Onodera, Masato, Toft, Sune, and Wang, Wei-Hao
- Subjects
galaxies: evolution ,galaxies: formation ,galaxies: high-redshift ,Astronomical and Space Sciences ,Atomic ,Molecular ,Nuclear ,Particle and Plasma Physics ,Physical Chemistry (incl. Structural) ,Astronomy & Astrophysics - Abstract
We have obtained three-dimensional maps of the universe in ∼200 × 200 × 80 comoving Mpc3 (cMpc3) volumes each at z = 5.7 and 6.6 based on a spectroscopic sample of 179 galaxies that achieves ⪆80% completeness down to the Lyα luminosity of, based on our Keck and Gemini observations and the literature. The maps reveal filamentary large-scale structures and two remarkable overdensities made out of at least 44 and 12 galaxies at z = 5.692 (z57OD) and z = 6.585 (z66OD), respectively, making z66OD the most distant overdensity spectroscopically confirmed to date, with >10 spectroscopically confirmed galaxies. We compare spatial distributions of submillimeter galaxies at z ≃ 4-6 with our z = 5.7 galaxies forming the large-scale structures, and detect a 99.97% signal of cross-correlation, indicative of a clear coincidence of dusty star-forming galaxy and dust-unobscured galaxy formation at this early epoch. The galaxies in z57OD and z66OD are actively forming stars with star-formation rates (SFRs) ⪆5 times higher than the main sequence, and particularly the SFR density in z57OD is 10 times higher than the cosmic average at the redshift (a.k.a. the Madau-Lilly plot). Comparisons with numerical simulations suggest that z57OD and z66OD are protoclusters that are progenitors of the present-day clusters with halo masses of ∼1014 M o˙
- Published
- 2019