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Time-delay cosmography with strongly lensed quasars measures the Hubble constant independently of the distance ladder and the CMB, but its accuracy is limited by the mass-sheet degeneracy (MSD), which lensing data alone cannot break. Stellar dynamics of the lens galaxy provides the missing information. I will present GLaD, a GPU-accelerated framework for self-consistent joint modeling of strong lensing and stellar dynamics, which reduces a full Bayesian analysis from months to days. Using simulated HST imaging and JWST-like IFU kinematics of the lensed quasar RXJ1131-1231, I will show that the MSD can be broken with a single lens, yielding 4% precision on H0, and I will discuss the first application to the real JWST observations of RXJ1131 and the practical challenges that dominate the real-data error budget. For the nearby lens ESO0286, the Einstein mass from HST extended-image modeling anchors triaxial Schwarzschild models of MUSE kinematics, tightening the outer mass profile and constraining the stellar initial mass function to be Kroupa-like, in contrast to the heavier IMFs reported at higher redshift.

BIO

Dr. Han Wang is a postdoctoral researcher at the Max Planck Institute for Astrophysics (MPA) in Garching, and will join the University of Oxford in October 2026 to work with Prof. Michele Cappellari. She received her Ph.D. in Physics from the Technical University of Munich in February 2026, under the supervision of Prof. Sherry Suyu, and also collaborates closely with Dr. Jens Thomas at the Max Planck Institute for Extraterrestrial Physics (MPE). Her research focuses on strong gravitational lensing and stellar dynamics, with applications to dark matter, the stellar initial mass function, and time-delay cosmography. She is the one of the main developers of GLaD, a GPU-accelerated framework for joint lensing and dynamical modeling, and a member of the TDCOSMO and Euclid collaborations.