Wednesday

Using one of the largest combinations of strong gravitational lens models (94 lens models of 74 cluster fields including 3 different lensing algorithms), we studied the impact of the lens mass distribution on the strong lensing efficiency. Our analysis revealed that among cluster-scale gravitational lenses, the flatter the density profile is the better the lens regardless of its total mass. I will explain in the presentation why this result appears contradictory to previous claims that more concentrated clusters have a higher lensing efficiency. However, many questions remain open regarding the physical processes originating such flat profiles. I will present our current investigation of the impact of substructures, namely cluster members galaxies, to the lensing potentials using VLT/MUSE IFU observations. Furthermore, our pilot study is using the fundamental plane to calibrate the mass-to-light ratio and to measure the most accurate mass possible of these cluster galaxies. Using such calibration, one can track the substructures mass ratio, providing a key ingredient into clusters’ evolution. In the end, one can use a large number of lensing clusters observations to answer fundamental questions on structure formation. While this study aims to compile a hundred clusters, it is only the stepping stone to upcoming surveys which will reveal thousands of lensing clusters.