Analysis of Increased Lensing Strength of Substructure in Galaxy Clusters

Abstract

In 2019, an inconsistency between our observations and our simulations was discovered. We were finding that there were more cases of strong lensing appearing around galaxy cluster substructure than was predicted in simulations. This project is born as an effort to provide reasoning for this unexplained discrepancy. We begin by looking for cases of gravitational lensing which include a galaxy cluster potential as well as a single galaxy potential which is contained within the cluster. By looking at the resultant Lens Equation and specifying the cases, we find an analytical expression for the behavior of resulting images. We next apply this expression to both observed and simulated data to look for the best set of parameters to minimize the amount of mass that the single galaxy needs to have the strongest lensing effect. Finally, we propose an explanation for why galaxy cluster substructure has more lensing strength in observations than in simulations. We believe that shallower cluster mass profiles result in stronger lensing potentials for many of the singular galaxies which make up the cluster.