Walls, Levi2016-07-252016-07-252016-07-23https://hdl.handle.net/11299/181436In order to account for the discrepancy in number of mass substructures seen in the dark matter halos of galaxies, gravitational lens-fitting simulations were performed to test whether the mass models used to describe these systems are unique. With no a priori knowledge, simulated quad-imaged lens systems were tested to see whether any effects due to any added dark matter substructure could be seen. The 𝜒² goodness-of-fit statistic, as well as average image separation and RMS of image separation were found to be below resolution thresholds, and conclusively illustrated that it is technically possible to fit a smooth mass model to a gravitational lens system with added substructure.enPresentation