Program: GS-2010B-Q-5

We propose a follow-up program of three galaxy clusters with strong arc candidates identified in the SOAR Gravitational Arc Survey (SOGRAS). The main aims are to confirm the gravitational lensing nature of these arcs and to provide mass estimates for the clusters from the velocity dispersion of their member galaxies. Besides the multi-object spectroscopy, we will obtain deeper imaging to search for new arcs and to determine properties of the lensed galaxies (sources) such as their stellar populations and star formation rate. Several techniques will be applied for constraining the mass distribution of the clusters (lenses) using the gravitational arc information. We will perform a combined dynamical plus strong lensing approach to obtain good constraints on the mass and dynamical state of the clusters. These data will also be used to test arc identification and characterization tools being developed by our group, including methods to enhance their detectability and arc finding algorithms. Finally, the results will help in understanding the selection function of SOGRAS, strengthening its goals of constraining the evolution of cluster structure through gravitational lensing.