Detailed dark matter maps of galaxy cluster substructure and direct comparison to simulations

Images from the next generation of telescopes will enable strikingly detailed reconstruction of the dark matter distributions in galaxy cluster cores using strong gravitational lensing analysis. This will provide a key test of Lambda-CDM cosmology on cluster scales where tensions currently exist. Observed dark matter distributions will be compared directly to those realized in simulations, forgoing any assumptions about light tracing mass. The required observations are deep, multicolor, and high-resolution, ideally supplemented with spectra of faint objects. ACS onboard HST is capable of obtaining images of sufficient quality, but for prohibitive integration times. The next generation of telescopes promises to efficiently yield the required images. An analysis method capable of processing the expected large numbers of multiple images has been developed (see below). The full range of constraints possible from analyzing these detailed mass maps is a matter of ongoing investigation.