The Gemini Planet Imager (GPI), is a facility class instrument for the Gemini Observatory with the primary goal of directly detecting young Jovian planets. After spending 2013 - 2020 at Gemini South, the instrument is currently undergoing maintenance and upgrades before its transition to Gemini North as GPI 2.0. Among the upgrades are significant changes to the Integral Field Spectrograph (IFS), including the installation of new prisms, Lyot stops/apodizers, and filters. The upgrades are expected to improve overall performance in the relevant wavelengths and angular separations needed for GPI 2.0.
The Gemini Planet Imager (GPI) is a high-contrast imaging instrument designed to directly detect and characterize young, Jupiter-mass exoplanets. After six years of operation at Gemini South in Chile, the instrument is being upgraded and relocated to Gemini North in Hawaii as GPI 2.0. GPI helped establish that Jovian-mass planets have a higher occurrence rate at smaller separations, motivating several sub-system upgrades to obtain deeper contrasts (up to 20 times improvement to the current limit), particularly at small inner working angles. This enables access to additional science areas for GPI 2.0, including low-mass stars, young nearby stars, solar system objects, planet formation in disks, and planet variability. The necessary instrumental changes required toenable these new scientific goals are to (i) the adaptive optics system, by replacing the current Shack-Hartmann Wavefront Sensor (WFS) with a pyramid WFS and a custom EMCCD, (ii) the integral field spectrograph, by employing a new set of prisms to enable an additional broadband (Y-K band) low spectral resolution mode, as well as replacing the pupil viewer camera with a faster, lower noise C-RED2 camera (iii) the calibration interferometer, by upgrading the low-order WFS used for internal alignment and on-sky target tracking with a C-RED2 camera and replacing the calibration high-order WFS used for measuring and correcting non-common path aberrations with a self coherent camera, (iv) the apodized-pupil Lyot coronagraph designs and (v) the software, to enable high-efficiency queue operations at Gemini North. GPI 2.0 is expected to go on-sky in early 2024. Here I will present the new scientific goals, the key upgrades, the current status and the latest timeline for operations.
The Keck Planet Imager and Characterizer (KPIC) is an instrument at the Keck II telescope that enables high-resolution spectroscopy of directly imaged exoplanets and substellar companions. KPIC uses single-mode fibers to couple the adaptive optics system to Keck’s near-infrared spectrometer (NIRSPEC). However, KPIC’s sensitivity at small separations is limited by the leakage of stellar light into the fiber. Speckle nulling uses a deformable mirror (DM) to destructively interfere starlight with itself, a technique typically used to reduce stellar signal on a focal-plane imaging detector. We present the first on-sky demonstration of speckle nulling through an optical fiber with KPIC, using NIRSPEC to collect exposures that measure speckle phase for quasi-real-time wavefront control while also serving as science data. We repeat iterations of measurement and correction, each using at least five exposures (four with DM probes to determine phase and one unprobed exposure to measure the intensity) and taking about 6 min when using 59.0 s exposures, including NIRSPEC overheads. We show a decrease in the on-sky leaked starlight by a factor of 2.6 to 2.8 in the targeted spectral order, at a spatial separation of 2.0 λ / D in K-band. This corresponds to an estimated factor of 2.6 to 2.8 decrease in the required exposure time to reach a given signal-to-noise ratio, relative to conventional KPIC observations. The performance of speckle nulling is limited by instability in the speckle phase: when the loop is opened, the null-depth degrades by a factor of 2 on the timescale of a single phase measurement, which would limit the suppression that can be achieved. Future work includes exploring gradient-descent methods, which may be faster and thereby able to achieve deeper nulls. In the meantime, the speckle nulling algorithm demonstrated in this work can be used to decrease stellar leakage and improve the signal-to-noise of science observations.
The Gemini Planet Imager (GPI) is a high contrast imaging instrument designed to directly detect and characterize young Jupiter-mass exoplanets. After six years of operation at Gemini South in Chile, the instrument is being upgraded and moved to Gemini North in Hawaii as GPI 2.0. As part of this upgrade, several improvements will be made to the adaptive optics (AO) system. This includes replacing the current Shack-Hartmann wavefront sensor (WFS) with a pyramid wavefront sensor (PWFS) and a custom EMCCD. These changes are expected to increase GPI’s sky coverage by accessing fainter targets, improving corrections on fainter stars and allowing faster and ultra-low latency operations on brighter targets. The PWFS subsystem is being independently built and tested to verify its performance before its integration into the GPI 2.0 instrument. In this paper, we will present the design and pre-integration test plan of the PWFS.
The Gemini Planet Imager (GPI) is a facility class instrument for the Gemini Observatory with the primary goal of directly detecting young Jovian planets. After several years of successful operations on sky at Gemini South, GPI is undergoing an upgrade at the University of Notre Dame and is being moved to Gemini North. We present the current performance results, from in-lab testing, for several of the upgraded components to the Integral Field Spectrograph (IFS) and the Calibration Wavefront Sensor (CAL) for GPI 2.0. These upgrades include changes to the IFS dispersion prisms, changes to the pupil viewing cameras, and changes to the low order wavefront sensor. These improvements are designed to improve the magnitude and contrast range of GPI. We describe the alignment of several components, their noise characteristics, and their performance in the GPI environment.
GPI is a facility instrument designed for the direct detection and characterization of young Jupiter mass exoplanets. GPI has helped establish that the occurrence rate of Jovian planets peaks near the snow line (~3 AU), and falls off toward larger separations. This motivates an upgrade of GPI to achieve deeper contrasts, especially at small inner working angles, to extend GPI’s operating range to fainter stars, and to broaden its scientific capabilities, all while leveraging its historical success. GPI was packed and shipped in 2022, and is undergoing a major science-driven upgrade. We present the status and purpose of the upgrades including an EMCCD-based pyramid wavefront sensor, broadband low spectral resolution prisms, new apodized-pupil Lyot coronagraph designs, upgrades of the calibration wavefront sensor and increased queue operability. We discuss the expected performance improvements and enhanced science capabilities to be made available in 2024.
Over the past six years the Gemini Planet Imager instrument has carried out adaptive-optics fed high-contrast imaging observations from the Gemini South telescope in Chile. GPI will now be upgraded for increased sensitivity and science capabilities as GPI 2.0, and will be moved to the Gemini North telescope in Hawaii. Here we describe tests we conducted remotely of the GPI instrument before shipment from Chile, and in-person following its arrival at the University of Notre Dame, where the upgrade will take place. These tests were originally designed to accommodate science program requirements and to ensure compatibility with the host observatory. We have now re-performed tests so as to assess the state of the instrument following six years of scientific performance. We present the high-level results of this baselining process, describe their implications and limitations, and compare them with results from tests performed when the original instrument was shipped to Chile in 2013.
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