Program: GS-2011B-Q-59

We propose a study of density profiles for MS0440.5+0204, combining strong lensing modeling and dynamical studies. MS0440 at z=0.19 has several arc systems including two radial lensing features, and looks "elliptical" from the symmetry of the distortion pattern of the gravitational arcs, making this galaxy cluster the ideal candidate to probe different mass profiles. We will use the GMOS instrument in multi-slit-spectroscopic mode to measure the redshifts of the brightest arcs and the galaxies in the cluster. We will use the data to test distinct density profiles on MS0440 by building a mass reconstruction from the strong lensing features observed with the HST/WFPC2 and reported by previous authors. Combining strong lensing modeling with the analysis of the kinematical structural parameters of the cluster member galaxies, we will characterize the density profile from the strong lensing region of the cluster up to "medium scales", discriminate quantitatively between different mass models and probe the slope of the mass profile.