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

We have started PISCES project; a panoramic imaging and spectroscopic surveyof distant clusters on Subaru. It exploits the unique wide-field imagingcapability of Suprime-Cam, which provides a 34'x27' field of view correspondingto a physical area of 16x13Mpc^2 at z~1. We plan to target 15 clusters in totalat 0.45Mpc from the cores, as well as complex innerstructures. The galaxy distributions in the inner regions of the clusters looksimilar to the X-ray intensity maps, suggesting that most of the opticalstructures trace physically bound systems. We also compared the structures ofthe three clusters with those of model clusters in a numerical simulation(N-body + semi-analytic model) by parameterising the shapes of the iso-densitycontours of galaxies, and found a broad agreement. Our results provide goodevidence that cluster-scale assembly takes place along filaments duringhierarchical clustering, while the structures found here need to be confirmedspectroscopically in the near future.Comment: 14 pages, 12 figures (of which 5 are provided in jpg format), uses pasj00.cls. PASJ in press. Proof corrected. Error in Fig.3 fixe