NOAO >   Observing Info >   Approved Programs >   2005A-0144

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Proposal Information for 2005A-0144


PI: Kim-Vy Tran, ETH Zurich, vy@phys.ethz.ch
Address: Institute for Astronomy, Zurich CH-8093, Switzerland

CoI: Marijn Franx, Leiden Observatory

Title: Near-Infrared Imaging of CL 1358+62 (z=0.33) and MS 2053-04 (z=0.59): The Fundamental Plane and Stellar Masses

Abstract: We propose to use FLAMINGOS on the KPNO 4m to obtain wide-field, JHK imaging of two massive galaxy clusters at z>0.3: CL 1358+62 at z=0.33 and MS 2053-04 at z=0.59. Combining near-IR photometry with internal velocity dispersions already in hand for 79 cluster galaxies, we will measure the Fundamental Plane (FP) in rest-frame I and J to provide robust measurements of evolution in the M/L ratios since z~0.6 as well as provide valuable checks on FP results obtained with photometry at shorter wavelengths. We also will use the near-IR fluxes to measure robust stellar masses for a total of 381 spectroscopically confirmed members (R_BCG\lesssim1h^-1 Mpc). By combining near-IR results in CL1358 and MS2053 with those already obtained for MS 1054-03 (z=0.83), we will test recent claims of ``down-sizing'' in clusters by focusing on the mass evolution of post- starburst and star-forming members. In conjunction with the extensive multi-wavelength data we have acquired for both clusters, the JHK imaging requested here will improve our overall understanding of how galaxies in rich clusters assembled their stars.


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NOAO >   Observing Info >   Approved Programs >   2005A-0144

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