Program: GN-2013B-Q-69

We have been awarded 25 orbits of HST WFC3 IR time to study the host galaxies of five faint z=6 quasars, using a point source subtraction technique. As part of our HST proposal, we were awarded 6 hours of NOAO Gemini time to pre-select PSF stars for the HST observations. 2.46 hours were allocated in semester 2013A and are currently queued. This proposal details the technical aspects for the remainder of this already-approved time request. The primary purpose of these observations is to reject those candidates that represent previously unknown binary systems that may be resolved at HST resolution. Each PSF star candidate is restricted to be within 5 degrees of its associated quasar, in order to match the HST thermal environment as closely as possible when imaging both quasar and PSF star. We therefore request 3.45 hr (The remaining ~60% of our alotted 6 hr) of NIRI+LGS AO time in semester 2013B to image 12 PSF star candidates for our final three quasars.