Special Physics Colloquium

Towards a detailed mapping of the small-scale distribution of dark matter with strong gravitational lensing, new surveys, and machine learning

Strong gravitational lensing providesa unique opportunity to investigate many subjects, including the distribution of dark matter in lensing galaxies, the properties of distant galaxies by magnifying their images, and the expansion rate of the universe. Today, however, there are only a few hundred strong lenses known and the study ofthese systems has been often limited to small samples, due to the challenging nature of lens modeling analysis. This is about to change. First, with the new generation of ground and space surveys, tens of thousands of strong lenses are expected to be discovered in the coming decade. Second, high-resolutiontelescopes, like the GMT, TMT, and ALMA, will provide exceptionally high-quality follow-up observations of many of the most interesting new lenses. Finally, our latest results show that thanks to recent advances in machine learning, the analysis of these systems can be done in a remarkably fast and automated way, allowing a detailed study of tens of thousands of gravitational lenses in a few seconds. In this talk, I will discuss these three components, which, I believe, will transform the landscape of strong lensing studies in thecoming decade. I will also highlight our ongoing work with ALMA to use strong lensing systems to detect low-mass dark matter subhalos. This project aims totest a key prediction of the cold dark matter model. I will discuss the futureof this work in the above-mentioned context.