Program: GN-2023B-Q-230

Strong gravitational lenses are a valuable tool in modern astrophysics. Measuring the time delays between the multiple images of variable sources (e.g. supernovae or quasars) allows for a direct measurement of the so called time-delay distance and thus can be used to measure cosmological parameters, in particular the Hubble constant, H0. Thus, if the lensing potential can be accurately modeled, the Hubble constant can be derived from measuring the difference in the light travel time of multiple images. We propose to obtain spectra for strongly lensed quasars with Gemini-North GMOS long slit observations in order to measure both lens and source redshifts. These redshifts will be used to priduce accurate lens models for these systems.