K
Kouji Ohta
Researcher at Hiroshima University
Publications - 452
Citations - 19379
Kouji Ohta is an academic researcher from Hiroshima University. The author has contributed to research in topics: Galaxy & Redshift. The author has an hindex of 67, co-authored 427 publications receiving 18444 citations. Previous affiliations of Kouji Ohta include University of Hawaii & Kitt Peak National Observatory.
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Journal ArticleDOI
Cosmological evolution of the hard X-ray active galactic nucleus luminosity function and the origin of the hard X-ray background
TL;DR: In this article, the cosmological evolution of the hard X-ray luminosity function (HXLF) of active galactic nuclei (AGNs) in the 2-10 keV luminosity range of 1041.5-1046.5 ergs s-1 was investigated.
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Cosmological Evolution of the Hard X-ray AGN Luminosity Function and the Origin of the Hard X-ray Background
TL;DR: In this article, the authors investigated the cosmological evolution of the hard X-ray luminosity function (HXLF) of Active Galactic Nuclei (AGN) in the 2-10 keV luminosity range of 10^{41.5} - 10^{46.5] erg s^-1 as a function of redshift up to 3.8*10^{-15} erg cm^-2 s
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The End of the Reionization Epoch Probed by Lyα Emitters at z = 6.5 in the Subaru Deep Field* **
Nobunari Kashikawa,Kazuhiro Shimasaku,Matthew A. Malkan,Mamoru Doi,Yuichi Matsuda,Masami Ouchi,Yoshiaki Taniguchi,Chun Ly,Tohru Nagao,Masanori Iye,Kentaro Motohara,Takashi Murayama,Kouji Murozono,Kyoji Nariai,Kouji Ohta,Sadanori Okamura,Toshiyuki Sasaki,Yasuhiro Shioya,Masayuki Umemura +18 more
TL;DR: In this article, an extensive search for Lyα emitters (LAEs) at z = 6.5 in the Subaru Deep Field was conducted, which revealed an apparent deficit at the bright end of ∼ 0.75 mag fainter L*, compared with that observed at z=5.7.
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The Cosmic Evolution Survey (COSMOS): Subaru observations of the HST cosmos field
Yoshiaki Taniguchi,Nick Scoville,Nick Scoville,T. Murayama,David B. Sanders,Bahram Mobasher,Herve Aussel,Peter Capak,M. Ajiki,Satoshi Miyazaki,Yutaka Komiyama,Yasuhiro Shioya,Tohru Nagao,Shunji S. Sasaki,Shunji S. Sasaki,Shunji S. Sasaki,Jin Koda,Chris Carilli,Mauro Giavalisco,Luigi Guzzo,Günther Hasinger,Chris Impey,O. LeFevre,Simon J. Lilly,Alvio Renzini,Michael Rich,Eva Schinnerer,Patrick L. Shopbell,Norio Kaifu,Hiroshi Karoji,Nobuo Arimoto,Sadanori Okamura,Kouji Ohta +32 more
TL;DR: In this article, the authors presented deep optical imaging observations of 2 square degree area, covered by the Cosmic Evolution Survey (COSMOS), made by the prime-focus camera (Supreme-Cam) on the 8.2 m Subaru Telescope.
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A Subaru Search for Lyα Blobs in and around the Protocluster Region At Redshift z = 3.1
Yuichi Matsuda,Toru Yamada,Tomoki Hayashino,Hajime Tamura,R. Yamauchi,Masaru Ajiki,Shinobu S. Fujita,Takashi Murayama,Tohru Nagao,Kouji Ohta,Sadanori Okamura,Masami Ouchi,Kazuhiro Shimasaku,Yasuhiro Shioya,Yoshiaki Taniguchi +14 more
TL;DR: In this article, the authors report the properties of 35 robust candidate Lyα blobs (LABs) which are larger than 16 arcsec2 in isophotal area and brighter than 0.7 × 10-16 ergs s-1 cm-2, located in and around the protocluster region at redshift z = 3.3 × 105 Mpc3.