CONICET | Buscador de Institutos y Recursos Humanos

The recent commissioning of the Gemini MCAO system (GeMs) sets the stage for its use with the near-IR spectrometer F2. In this poster, we describe the upcoming work left to do to be able to start the commissioning of F2 with GEMs. This combination will provide the Gemini community with one of the few AO fed MOS near-IR spectrometers on a 8m class telescope. Preliminary performance tests of GeMS with GMOS-S indicate that the MCAO correction provides, over a 2 arcmin field, images with a typical uniform PSF of 0.2 arcsec in the z band (from 0.08 to 0.35 depending on the natural seeing). Under similar conditions, the resulting strehl ratio in GSAOI images is in the range 25-35% for the H band. At f/33 the FOV of F2 is 3 arcmin and larger than the FOV at GSAOI (80 arcsec). F2 images during commissioning of the f/16 mode have shown that the instrument can provide an image quality of 2 pixels, which correspond to 0.18 arcsec with the f/33 GeMS beam. As such, a typical 2-pixel slit would provide reasonable compromise to efficiently couple a large fraction (80%) of the incident starlight into the instrument during relatively long exposures. We are focusing on a few typical science cases in order to refine the requirements for commissioning. The cases are: spectroscopy of very faint source (long slit mode) and spectroscopy of many faint sources (MOS). For both cases we have to determine suitable acquisition techniques and characterize the final throughput of the whole system. For longslits we will need to improve the blind offset acquisition to a precision of 0.1 arcsec for an offset star within 30 arcsec. For MOS, we need to characterize the differential refraction and atmospheric dispersion constraints, and refine the mask making process. In the future we would like to also implement changes in the readout so that fast MOS acquisitions can be achieved by reading subregions of the chip.