2018ApJ...863...60R

Galaxy clusters can act as gravitational lenses and magnify the universe behind them, allowing us to see deep into the early universe. The Hubble Space Telescope Frontier Fields program uses six galaxy clusters imaged by Hubble to discover and study galaxies at z ∼ 5-10. Seven independent teams developed lens models and derived magnifications for each galaxy cluster, based on positional and redshift constraints from the best available data at the time. In this work we evaluate 10 models for MACS J0416.1-2403 that were made public in 2015 by contrasting them with new spectroscopic redshifts that were measured in 2016. We developed an independent comparison method that uses the source plane root-mean-square as a metric of lensing model performance. Our analysis quantifies the ability of models to predict unknown multiple images. We examine the source plane scatter of multiply imaged systems and explore the dependence of the scatter on the location and the redshift of the background sources. The analysis we present evaluates the performance of the different algorithms in the specific case of the MACS J0416.1-2403 models.