Program: GN-2015B-Q-27

We propose multi-object spectroscopy of the field of the newly-discovered large separation quasar, SDSSJ2222+2745. This system is only the third known of its kind. It has the highest quasar redshift (z=2.8), and uniquely features the largest observed image multiplicity (at least 6), with at least three images close to the cluster core. We have multiband HST imaging (Cycle 21, PI Sharon) and Swift and Chandra observations are scheduled. The proposed Gemini spectroscopy will: secure redshifts for the other lensed galaxies in the field, which will supply critical constraints for the lens model, characterize the magnified, spatially resolved host galaxy of the quasar, probe intervening absorbers along the line of sight to the quasar, and constrain the mass distribution of the lensing galaxy cluster.