Takatoshi ShibuyaMasami OuchiYuichi HarikaneMichael RauchYoshiaki OnoShiro MukaeRyo HiguchiTakashi KojimaSuraphong YumaChien Hsiu LeeHisanori FurusawaAkira KonnoCrystal L. MartinKazuhiro ShimasakuYoshiaki TaniguchiMasakazu A.R. KobayashiMasaru KajisawaTohru NagaoTomotsugu GotoNobunari KashikawaYutaka KomiyamaHaruka KusakabeRieko MomoseKimihiko NakajimaMasayuki TanakaShiang Yu WangResearch Center for the Early UniverseNational Institutes of Natural Sciences - National Astronomical Observatory of JapanUniversity of California, Santa BarbaraUniversity of TokyoEuropean Southern ObservatoryThe Graduate University for Advanced StudiesNational Tsing Hua UniversityThe Open University of JapanMahidol UniversityNational Taiwan UniversityCarnegie ObservatoriesEhime UniversityNational Institute of Technology2019-08-232019-08-232018-01-01Publications of the Astronomical Society of Japan. Vol.70, (2018)2053051X000462642-s2.0-85041677403https://repository.li.mahidol.ac.th/handle/20.500.14594/45751© The Author 2017. Published by Oxford University Press on behalf of the Astronomical Society of Japan. All rights reserved. We present Lyα and UV-nebular emission line properties of bright Lyα emitters (LAEs) at z = 6-7 with a luminosity of log LLyα/[erg s-1] = 43-44 identified in the 21 deg2 area of the SILVERRUSH early sample developed with the Subaru Hyper Suprime-Cam survey data. Our optical spectroscopy newly confirms 21 bright LAEs with clear Lyα emission, and contributes to making a spectroscopic sample of 96 LAEs at z = 6-7 in SILVERRUSH. From the spectroscopic sample, we select seven remarkable LAEs as bright as Himiko and CR7 objects, and perform deep Keck/MOSFIRE and Subaru/nuMOIRCS near-infrared spectroscopy reaching the 3 σ flux limit of ∼2 × 10-18 erg s-1 for the UV-nebular emission lines of He II λ1640, CIV λλ1548,1550, and OIII]λλ1661,1666. Except for one tentative detection of C IV, we find no strong UV-nebular lines down to the flux limit, placing the upper limits of the rest-frame equivalent widths (EW0) of ∼2-4 A for CIV, He II, and OIII] lines. We also investigate the VLT/X-SHOOTER spectrum of CR7 whose 6 σ detection of He II is claimed by Sobral et al. Although two individuals and the ESO archive service carefully reanalyzed the X-SHOOTER data that are used in the study of Sobral et al., no He II signal of CR7 is detected, supportive of weak UV-nebular lines of the bright LAEs even for CR7. The spectral properties of these bright LAEs are thus clearly different from those of faint dropouts at z ∼ 7 that have strong UV-nebular lines shown in the various studies. Comparing these bright LAEs and the faint dropouts, we find anti-correlations between the UV-nebular line EW0 and the UV-continuum luminosity, which are similar to those found at z ∼ 2-3.Mahidol UniversityEarth and Planetary SciencesPhysics and AstronomyArticleSCOPUS10.1093/pasj/psx107