Pushing the Boundaries of the Cl 1604 Supercluster atz ~ 0.9

The Cl 1604 supercluster at z~0.9 is known to contain at least four distinctmember clusters, separated in both projection and redshift. In this paper wepresent deep, multicolor wide-field imaging of a region spanning ~45' on aside, corresponding to 21 h^{-1}_{70} Mpc (physical) at the superclusterredshift. We select galaxies whose colors correspond to those ofspectroscopically confirmed cluster members in the r' vs. (r'-i')color-magnitude diagram. Using an adaptive kernel, we generate a map of theprojected red galaxy density and identify numerous new candidate clusters whichare likely supercluster members. Assuming that all of the density peaks areassociated with the supercluster, its transverse size is ~10 h^{-1}_{70} Mpc,which is still significantly smaller than the nearly 93 h^{-1}_{70} Mpc depthin redshift space.Comment: 5 pages, 5 figures. Accepted for publication in AJ. Figures and text updated with correction