Gravitational Lens Modeling of Doubly Imaged Quasars

Authors: Ryan Brady, Simon Birrer, Xiangyu Huang

SUNY Campus: Stony Brook University

Presentation Type: Poster

Location: Old Union Hall

Presentation #: 42

Timeslot: Session C 1:45-2:45 PM

Abstract: Gravitational lensing is a phenomenon predicted by Einstein’s general theory of relativity, wherein light from a distant source is bent by the curvature of spacetime around a massive foreground object. In strong lensing systems, this effect can produce multiple images of the background source, such as a quasar, with photons from each image traveling along distinct geodesics. These varying light paths introduce measurable time delays between the arrival of photons from different images, providing a unique opportunity to probe cosmological parameters. In particular, computational modeling of gravitational lensing systems allows for the prediction of these photon time delays, offering a new method for inferring the Hubble constant. In this study, we present models of doubly imaged quasars observed by the Hubble Space Telescope using Lenstronomy, a Python-based gravitational lensing analyzation library. Our modeling approach accounts for parameters such as lens mass profiles, external shear, and source morphology to refine constraints on lensing system properties. Using these models, our goal is to measure the Hubble constant to a few percent precision by accurately determining the time delays between quasar images. By doing so, we also establish a framework for future analyses of doubly imaged quasars with larger datasets from upcoming astronomical surveys, such as the Legacy Survey of Space and Time (LSST). This work is supported with funding from the National Aeronautics and Space Administration (NASA) and the NASA New York Space Grant Consortium.