Ryuji Hata
Kyoto University
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Featured researches published by Ryuji Hata.
Publications of the Astronomical Society of Japan | 2001
Toshinori Maihara; Fumihide Iwamuro; Hirohisa Tanabe; Tomoyuki Taguchi; Ryuji Hata; Shin Oya; Nobunari Kashikawa; Masanori Iye; Satoshi Miyazaki; Hiroshi Karoji; Michitoshi Yoshida; Tomonori Totani; Yuzuru Yoshii; Sadanori Okamura; Kazuhiro Shimasaku; Yoshihiko Saito; Hiroyasu Ando; Miwa Goto; Masahiko Hayashi; Norio Kaifu; Naoto Kobayashi; George Kosugi; Kentaro Motohara; Tetsuo Nishimura; Jun’ichi Noumaru; Ryusuke Ogasawara; Toshiyuki Sasaki; Kazuhiro Sekiguchi; Tadafumi Takata; Hiroshi Terada
Deep near-infraredimages of a blank 2 � ×2 � section of skynear the galactic north pole taken by Subaru Telescope are presented. The total integration times of the J and Kbands were 12.1 hr and 9.7 hr, resulting in 5 σ limiting magnitudes of 25.1 and 23.5 mag, respectively. The numbers of sources within these limiting magnitudes found with an automated detection procedure are 385 in the J band and 350 in K � . Based on photometric measurements of these sources, we present number count vs. magnitude relations, color vs. magnitude diagrams, size vs. color relationships, etc. The slope of the galaxy number count plotted against the AB magnitude scale is about 0.23 in the 22 to 26 AB magnitude range of both bands. The spatial number density of galaxies as well as the slopes in the faint-end region given by the Subaru Deep Field (SDF) survey are consistent with those given by HST-NICMOS surveys, as expressed on the AB magnitude diagram. Several sources having very large J − Kcolor have been found, including a few Kobjects without detection at J. In addition, a number of faint galactic stars were also
Publications of the Astronomical Society of Japan | 2001
Fumihide Iwamuro; Kentaro Motohara; Toshinori Maihara; Ryuji Hata; Takashi Harashima
This paper describes an OH-airglow Suppressor (OHS) for the infrared Nasmyth focus of the Subaru telescope. OHS has the capability of eliminating 224 airglow-lines in the
Publications of the Astronomical Society of Japan | 2000
Tadashi Nakajima; Takashi Tsuji; Toshinori Maihara; Fumihide Iwamuro; Kentaro Motohara; Tomoyuki Taguchi; Ryuji Hata; Motohide Tamura; Takuya Yamashita
J
Publications of the Astronomical Society of Japan | 2000
Youichi Ohyama; Michitoshi Yoshida; Tadafumi Takata; Masatoshi Imanishi; Tomonori Usuda; Yoshihiko Saito; Hiroko Taguchi; Noboru Ebizuka; Fumihide Iwamuro; Kentaro Motohara; Tomoyuki Taguchi; Ryuji Hata; Toshinori Maihara; Masanori Iye; Toshiyuki Sasaki; George Kosugi; Ryusuke Ogasawara; Junichi Noumaru; Yoshihiko Mizumoto; Masafumi Yagi; Yoshihiro Chikada
- and
Publications of the Astronomical Society of Japan | 2000
Fumihide Iwamuro; Kentaro Motohara; Toshinori Maihara; Jun'ichi Iwai; Hirohisa Tanabe; Tomoyuki Taguchi; Ryuji Hata; Hiroshi Terada; Miwa Goto; Shin Oya; Masanori Iye; Michitoshi Yoshida; Hiroshi Karoji; Ryusuke Ogasawara; Kazuhiro Sekiguchi
H
Publications of the Astronomical Society of Japan | 2001
Kentaro Motohara; Toru Yamada; Fumihide Iwamuro; Ryuji Hata; Tomoyuki Taguchi; Takashi Harashima; Toshinori Maihara; Masanori Iye; Chris Simpson; Michitoshi Yoshida
-bands, which are major sources of background radiation at near-infrared wavelengths up to 2
Publications of the Astronomical Society of Japan | 2000
Toru Yamada; Masaru Kajisawa; Ichi Tanaka; Toshinori Maihara; Fumihide Iwamuro; Hiroshi Terada; Miwa Goto; Kentaro Motohara; Hirohisa Tanabe; Tomoyuki Taguchi; Ryuji Hata; Masanori Iye; Masatoshi Imanishi; Yoshihiro Chikada; Michitoshi Yoshida; Chris Simpson; Toshiyuki Sakaki; George Kosugi; Tomonori Usuda; Koji Omata; Katsumi Imi
\mu
Publications of the Astronomical Society of Japan | 2000
Norio Kaifu; Tomonori Usuda; Saeko S. Hayashi; Yoichi Itoh; Masayuki Akiyama; Takuya Yamashita; Yasushi Nakajima; Motohide Tamura; Shu-ichiro Inutsuka; Masahiko Hayashi; Toshinori Maihara; Fumihide Iwamuro; Kentaro Motohara; Jun'ich Iwai; Hirohisa Tanabe; Tomoyuki Taguchi; Ryuji Hata; Hiroshi Terada; Miwa Goto; Hiroyasu Ando; T. Aoki; Yoshihiro Chikada; Mamoru Doi; Noboru Ebizuka; Takeo Fukuda; Masaru Hamabe; Tetsuo Hasegawa; Toshihiro Horaguchi; Shin-ichi Ichikawa; Takashi Ichikawa
m. Specifically, it is a pre-optics system installed between the telescope and an infrared camera/spectrograph (CISCO). The suppressor reduces sky background emissions to 1/25 and its throughput is 40%. As a result, the S/N gain achieved with OHS is more than 1 mag compared to the typical spectroscopic approach. The limiting magnitude measured during a test observing run was found to be
Publications of the Astronomical Society of Japan | 2002
Kentaro Motohara; Fumihide Iwamuro; Toshinori Maihara; Shin Oya; Hiroyuki Tsukamoto; Masatoshi Imanishi; Hiroshi Terada; Miwa Goto; Jun Ichi Iwai; Hirohisa Tanabe; Ryuji Hata; Tomoyuki Taguchi; Takashi Harashima
H
Publications of the Astronomical Society of Japan | 2000
Yoichi Itoh; Norio Kaifu; Masahiko Hayashi; Saeko S. Hayashi; Takuya Yamashita; Tomonori Usuda; Junichi Noumaru; Toshinori Maihara; Fumihide Iwamuro; Kentaro Motohara; Tomoyuki Taguchi; Ryuji Hata
= 21.1 mag (
