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arXiv · 1704.08140

SILVERRUSH. II. First Catalogs and Properties of ~2,000 Lya Emitters and Blobs at z~6-7 Identified over the 14-21 deg2 Sky

Takatoshi Shibuya·Masami Ouchi·Akira Konno·Ryo Higuchi·Yuichi Harikane·Yoshiaki Ono·Kazuhiro Shimasaku·Yoshiaki Taniguchi·Masakazu A. R. Kobayashi·Masaru Kajisawa·Tohru Nagao·Hisanori Furusawa·Tomotsugu Goto·Nobunari Kashikawa·Yutaka Komiyama·Haruka Kusakabe·Chien-Hsiu Lee·Rieko Momose·Kimihiko Nakajima·Masayuki Tanaka·Shiang-Yu Wang·Suraphong Yuma
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Abstract

We present an unprecedentedly large catalog consisting of 2,230 > L* Lya emitters (LAEs) at z=5.7 and 6.6 on the 13.8 and 21.2 deg2 sky, respectively, that are identified by the SILVERRUSH program with the first narrowband imaging data of the Hyper Suprime-Cam (HSC) survey. We confirm that the LAE catalog is reliable on the basis of 96 LAEs whose spectroscopic redshifts are already determined by this program and the previous studies. This catalogue is also available on-line. Based on this catalogue, we derive the rest-frame Lya equivalent-width distributions of LAEs at z~5.7-6.6 that are reasonably explained by the exponential profiles with the scale lengths of ~120-170A, showing no significant evolution from z~5.7 to z~6.6. We find that 275 LAEs with a large equivalent width (LEW) of >240A are candidates of young-metal poor galaxies and AGNs. We also find that the fraction of LEW LAEs to all ones is 4% and 21% at z~5.7 and z~6.6, respectively. Our LAE catalog includes 11 Lya blobs (LABs) that are LAEs with spatially extended Lya emission whose profile is clearly distinguished from those of stellar objects at the >~ 3sigma level. The number density of the LABs at z=6-7 is ~ 10^-7-10^-6 Mpc^-3, being ~ 10-100 times lower than those claimed for LABs at z~ 2-3, suggestive of disappearing LABs at z>~6, albeit with the different selection methods and criteria for the low and high-z LABs.

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Takatoshi Shibuya, Masami Ouchi, Akira Konno, Ryo Higuchi, Yuichi Harikane, Yoshiaki Ono, Kazuhiro Shimasaku, Yoshiaki Taniguchi, Masakazu A. R. Kobayashi, Masaru Kajisawa, Tohru Nagao, Hisanori Furusawa, Tomotsugu Goto, Nobunari Kashikawa, Yutaka Komiyama, Haruka Kusakabe, Chien-Hsiu Lee, Rieko Momose, Kimihiko Nakajima, Masayuki Tanaka, Shiang-Yu Wang, Suraphong Yuma. 2017-04-26. SILVERRUSH. II. First Catalogs and Properties of ~2,000 Lya Emitters and Blobs at z~6-7 Identified over the 14-21 deg2 Sky. https://doi.org/10.1093/pasj/psx122

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