Events · Journal Talk
Journal Talk 22: Nafis Sadik Nihal (2026)
Automated Modeling of Gravitational Lenses from the Hubble Space Telescope.
Automated Modeling of Gravitational Lenses from the Hubble Space Telescope.
Abstract
Strong gravitational lensing is a powerful astrophysical tool for probing galaxy structure, dark matter properties, and the expansion history of the Universe. In this talk, I will present an automated and efficient approach to modeling galaxy-scale strong gravitational lenses using DOLPHIN, a forward-modeling pipeline built on top of Lenstronomy. The analysis is based on Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) imaging in the F814W filter.
DOLPHIN combines a deep-learning–based segmentation module with automated lens-model configuration to minimize manual intervention while retaining the flexibility for semi-automated refinement. The pipeline automatically identifies and labels the lens galaxy light, lensed arcs, satellite galaxies, quasar images, and background regions. It then constructs lens models that include the lens mass distribution, lens and source light profiles, and quasar point sources.
The resulting models provide key physical parameters, including the Einstein radius, mass profile slope, ellipticity, external shear strength and orientation, Sérsic parameters of the lens and source light, and quasar image positions and fluxes. This automated framework significantly reduces model preparation time, ensures a consistent treatment of large samples, and delivers robust measurements for statistical studies. The results demonstrate DOLPHIN’s capability to efficiently model large samples of lensed quasars, enabling rapid system characterization and facilitating future follow-up observations and cosmographic analyses.
Presenter: Nafis Sadik Nihal (Postbac Research Assistant at CASSA; B.Sc. in Electrical and Electronics Engineering, Islamic University of Technology, Dhaka)
Supervisor: Dr. Anowar Jaman Shajib (Associate Member at CASSA; KICP & NASA Einstein Fellow, Department of Astronomy & Astrophysics, The University of Chicago, IL, USA)
To get notifications, subscribe using the Google Form: