The Gemini High-Resolution Optical SpecTrograph (GHOST)

Abstract

The Gemini High-Resolution Optical SpecTrograph (GHOST) is the newest instrument chosen for the Gemini South telescope. It is being developed by a collaboration between the Australian Astronomical Observatory (AAO), the NRC - Herzberg in Canada and the Australian National University (ANU). Using recent technological advances and several novel concepts it will deliver spectroscopy with R>50,000 for up to 2 objects simultaneously or R>75,000 for a single object. GHOST uses a fiber-image-slicer to allow use of a much smaller spectrograph than that nominally required by the resolution-slit–width product. With its fiber feed, we expect GHOST to have a sensitivity in the wavelength range between 363-950 nm that equals or exceeds that of similar directly-fed instruments on world-class facilities. GHOST has entered the build phase. We report the status of the instrument and describe the technical advances and the novel aspects, such as the lenslet-based slit reformatting. Finally, we describe the unique scientific role this instrument will have in an international context, from exoplanets through stellar elemental abundances to the distant Universe. Keywords: Gemini, spectrograph, spectroscopy, echelle, high resolution, radial velocity, fiber image slicer, integral field unit.