Gemini High-resolution Optical SpecTrograph (GHOST) at Gemini-South: Instrument performance and integration, first science, and next steps

TL;DR

GHOST is a high-resolution spectrograph at Gemini-South enabling efficient, precise spectroscopy of various targets, with demonstrated performance and new scientific opportunities since its installation in 2022.

Contribution

This paper reports the successful integration, performance evaluation, and initial scientific results of the GHOST spectrograph at Gemini-South, highlighting its capabilities and future upgrades.

Findings

Achieved high efficiency and precision in spectroscopic observations

Demonstrated ability to observe targets down to V~20.8 mag

Enabled new high-resolution spectroscopy research avenues

Abstract

The Gemini South telescope is now equipped with a new high-resolution spectrograph called GHOST (the Gemini High-resolution Optical SpecTrograph). 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 76000 or 56000, and can reach a SNR$\sim$5 in a 1hr exposure on a V$\sim$20.8 mag target in median site seeing, and dark skies (per resolution element). GHOST was installed on-site in June 2022, and we report performance after full integration to queue operations in November 2023, 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.