Gemini High-resolution Optical Spectrograph (GHOST) at Gemini South

Abstract

The Gemini South telescope is now equipped with a new high-resolution spectrograph called the Gemini High-resolution Optical SpecTrograph (GHOST). This instrument provides high-efficiency, high-resolution spectra covering 347–1060 nm in a single exposure of either one or two targets simultaneously, along with precision radial velocity spectroscopy utilizing an internal calibration source. It can operate at a spectral element resolving power of either 76,000 or 56,000, and can reach a signal-to-noise ratio of ∼5 in a 1 hr exposure on a V ∼ 20.8 mag target in median site seeing and dark skies (per resolution element). GHOST was installed on-site in 2022 June, and we report performance after full integration to queue operations in 2023 November, in addition to scientific results enabled by the integration observing runs. These results demonstrate the ability to observe a wide variety of bright and faint targets with high efficiency and precision. With GHOST, new avenues to explore high-resolution spectroscopy have opened up to the astronomical community. These are described, along with the planned and potential upgrades to the instrument. Show more