COOL-LAMPS: Characterizing the size and star formation history of a strongly lensed early-type z=1 galaxy

We report the discovery of COOL-J1323+0343, a strongly lensed galaxy at z=1.0153 ± 0.0006, lensed by a galaxy cluster at z=0.353 ± 0.001. It was discovered by the COOL-LAMPS (ChicagO Optically-selected strong Lenses - Located At the Margins of Public Surveys) collaboration. From ground-based grzH imaging and optical spectroscopy, we model its stellar populations via the Prospector SED-fitting framework, and inferred via parametric and non-parametric star-formation histories. From lens modeling, we report the magnification and reconstruct the lensed galaxy in the source plane. From this we measure the morphology and size of the source galaxy, and contextualize this against the measured evolution of early type galaxies at z=1. This object is a good candidate for follow up with larger telescopes at higher resolution (both spectral and spatial), as a source plane reconstruction at higher resolution, and spectrum sufficient to measure the galaxy’s velocity structure would be a significant datapoint in the story of ETG evolution.