PI: Anthony Gonzalez, University of Florida, firstname.lastname@example.org
Address: Department of Astronomy, Gainesville, FL 32611-2055, USA
CoI: Kim-Vy Tran, Harvard-Smithsonian Center for Astrophysics
Title: Life Before the Fall: Galaxy Cluster Assembly at z=0.37
Abstract: We request two nights of time on the KPNO 4m to obtain deep, wide- area J and K_s imaging of the supergroup SG1120 at z=0.37. Our existing \it Chandra observations and VIMOS spectroscopy show that SG1120 is composed of at least 4 individual galaxy groups that are bound to each other with a total combined mass comparable to the Coma cluster. The SG1120 complex thus provides a unique opportunity for determining whether ``pre-processing'' in the group environment is responsible for the bulk of observed differences between galaxies in nearby clusters and those in the field. The requested NIR imaging will be used in conjunction with our ACS and VIMOS imaging of the field to derive photometric redshifts for all cluster members. This information will be used both for future selection of spectroscopic targets and to determine stellar masses of cluster galaxies.
National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360