Subaru First-Light Deep Photometry of Galaxies in A 851 Field
Authors: Iye Masanori , Iwamuro Fumihide , Maihara Toshinori , Miyazaki Satoshi , Okamura Sadanori , Shimasaku Kazuhiro , Simpson Chris , Akiyama Masayuki , Ando Hiroyasu , Aoki Tetsuo , Aoki Tsutomu , Chikada Yoshihiro , Doi Mamoru , Ebizuka Noboru , Fukuda Takeo , Furusawa Hisanori , Goto Miwa , Hamabe Masaru , Hata Ryuji , Hayashi Masahiko , Hayashi Saeko S. , Horaguchi Toshihiro , Ichikawa Shinichi , Ichikawa Takashi , Imanishi Masatoshi , Imi Katsumi , Inata Motoko , Isobe Shuzo , Itoh Yoichi , Iwai Junichi , Kaifu Norio , Kamata Yukiko , Kanzawa Tomio , Karoji Hiroshi , Kashikawa Nobunari , Kato Taichi , Kawasaki Wataru , Kimura Masahiko , Kobayashi Naoto , Kobayashi Yukiyasu , Kodaira Keiichi , Komiyama Yutaka , Kosugi George , Kurakami Tomio , Mikami Yoshitaka , Miyashita Akihiko , Miyata Takashi , Mizumoto Yoshihiko , Motohara Kentaro , Nakagiri Masao , Nakajima Koich , Nakamura Kyoko , Nakata Fumiaki , Nariai Kyoji , Nishihara Eiji , Nishikawa Jun , Nishimura Shiro , Nishimura Tetsuo , Nishino Tetsuo , Noguchi Kunio , Noguchi Takeshi , Noumaru Junichi , Ogasawara Ryusuke , Okada Norio , Okita Kiichi , Omata Koji , Oshima Norio , Otsubo Masashi , Oya Shin , Sasaki Goro , Sasaki Toshiyuki , Sawada Yasuhiro , Sekiguchi Kazuhiro , Sekiguchi Maki , Shelton Ian , Suto Hiroshi , Suzuki Katsuyuki , Taguchi Tomoyuki , Takami Hideki , Takata Tadafumi , Takato Naruhisa , Tamura Motohide , Tanabe Hirohisa , Tanaka Kyoko , Tanaka Wataru , Terada Hiroshi , Tomono Daigo , Torii Yasuo , Tsukamoto Hiroyuki , Usuda Tomonori , Watanabe Junichi , Watanabe Masaru , Yagi Masafumi , Yamashita Takuya , Yamashita Yasumasa , Yasuda Naoki , Yoshida Michitoshi , Yoshida Shigeomi , Yutani Masami 
Published: March 2014

We report on the results of optical and near-infrared photometry of the cluster of galaxies A 851 (= CL 0939+4713) carried out as one of the first-light observations of the 8.2 m Subaru telescope on Mauna Kea. Images as sharp as 0″.3 FWHM in K′ and 0″.45 in R were obtained in these observations. The 3σ limiting magnitudes for points sources in 0″.3 seeing with a 0″.6 software aperture were shown to go down to R = 28.1, J = 25.1, and K′; = 24.0, respectively, for about 1 hour integration. Subaru photometry of the galaxies in this cluster has shown in its color-magnitude diagrams a well-defined sequence of the early-type galaxy population that is consistent with the track predicted for a single-burst passive-evolution model of galaxies at z = 0.4. We attempted a morphological classification of galaxies in the Subaru R-band image using the Cin method, and found that discrimination between ellipticals and spirals can be achieved fairly consistently with the types assigned by MORPHs on the HST F702W image down to R &lt; 23. A weak lensing analysis made on the Subaru R-band image yielded a reconstructed surface mass-density distribution that shows a significant maximum corresponding to the peak of the smoothed luminosity distribution of cluster galaxies. We found no significant excess of faint and/or small galaxies in the putative cluster area around the z = 2 quasar and no difference in the colors for galaxies in this area from those in the main cluster either. Two extremely red objects (ERO) with R – K &gt; 6 are newly identified in the field. The colors of the reddest, disk-shaped galaxy R1 are found compatible with those of an unreddened E/S0 galaxy at z = 1.6.