Panoramic Views of Cluster-Scale Assemblies Explored by Subaru Wide-Field Imaging

• Published in: Publications of the Astronomical Society of Japan 2005-04, Vol.57 (2), p.309-323
• Main Authors: Kodama, Tadayuki, Tanaka, Masayuki, Tamura, Takayuki, Yahagi, Hideki, Nagashima, Masahiro, Tanaka, Ichi, Arimoto, Nobuo, Futamase, Toshifumi, Iye, Masanori, Karasawa, Yoshikazu, Kashikawa, Nobunari, Kawasaki, Wataru, Kitayama, Tetsu, Matsuhara, Hideo, Nakata, Fumiaki, Ohashi, Takaya, Ohta, Kouji, Okamoto, Takashi, Okamura, Sadanori, Shimasaku, Kazuhiro, Suto, Yasushi, Tamura, Naoyuki, Umetsu, Keiichi, Yamada, Toru
• Format: Article
• Language: English
• ISSN: 0004-6264; 2053-051X
• DOI: 10.1093/pasj/57.2.309

We have started PISCES project; a panoramic imaging and spectroscopic survey of distant clusters on Subaru. It exploits the unique wide-field imaging capability of Suprime-Cam, which provides a $34^{\prime} \times 27^{\prime}$ field of view corresponding to a physical area of $16 \times 13 \,\mathrm{Mpc}^2$ at $z \sim 1$ . We plan to target 15 clusters at $0.4 \lesssim z \lesssim 1.3$ . We report on our first results concerning the inner structures and large-scale structures of two distant clusters at $z = 0.55$ and 0.83 together with the earlier results on a $z = 0.41$ cluster. The photometric redshift technique has been applied to multi-color data in order to remove most of the foreground/background galaxies so as to isolate the cluster member candidates. We have found large-scale filamentary structures around the clusters, extending out to $\gt 5 \,\mathrm{Mpc}$ from the cores, as well as complex inner structures. The galaxy distributions in the inner regions of the clusters look similar to the X-ray intensity maps, suggesting that most of the optical structures trace physically bound systems. We also compared the structures of the three clusters with those of model clusters in a numerical simulation ( $N$ -body + semi-analytic model) by parameterising the shapes of the iso-density contours of galaxies, and found a broad agreement. Our results that cluster-scale assembly takes place along filaments during hierarchical clustering need to be confirmed spectroscopically in the near future.