Astronomy Special Seminar

In 1704, Isaac Newton first speculated that gravity might bend light, a question posed more than two centuries before any observatory could answer it. In the three centuries since, gravitational lensing has become a powerful astrophysical tool for investigating invisible dark matter. Nowhere is this more evident than in the study of galaxy clusters, the most massive gravitationally bound objects in the Universe. JWST in particular has dramatically improved the quality of our lensing datasets, significantly advancing our understanding of the hidden mass distributions of galaxy clusters. Beyond expanding traditional lensing samples, JWST also enables robust measurements of a higher-order lensing effect known as flexion. Although flexion has been measured with HST, the signal is extremely sensitive to resolution, optics, and source statistics, all of which are areas where JWST excels. In this talk, I will trace the history of gravitational lensing through the modern era, introduce how lensing observables are used to reconstruct cluster mass distributions, and conclude with a new lens modeling algorithm designed to exploit high-quality JWST data for the detection of previously inaccessible dark matter substructure.