The GMT-Consortium Large Earth Finder (G-CLEF) will be a cross-dispersed, optical band echelle spectrograph to be delivered as the first light scientific instrument for the Giant Magellan Telescope (GMT) in 2022. G-CLEF is vacuumenclosed and fiber-fed to enable precision radial velocity (PRV) measurements, especially for the detection and characterization of low-mass exoplanets orbiting solar-type stars. The passband of G-CLEF is broad, extending from 3500Å to 9500Å. This passband provides good sensitivity at blue wavelengths for stellar abundance studies and deep red response for observations of high-redshift phenomena. The design of G-CLEF incorporates several novel technical innovations. We give an overview of the innovative features of the current design. G-CLEF will be the first PRV spectrograph to have a composite optical bench so as to exploit that material's extremely low coefficient of thermal expansion, high in-plane thermal conductivity and high stiffness-to-mass ratio. The spectrograph camera subsystem is divided into a red and a blue channel, split by a dichroic, so there are two independent refractive spectrograph cameras. The control system software is being developed in model-driven software context that has been adopted globally by the GMT. G-CLEF has been conceived and designed within a strict systems engineering framework. As a part of this process, we have developed a analytical toolset to assess the predicted performance of G-CLEF as it has evolved through design phases.
We present the results of high-resolution near-IR spectroscopy toward the multiple outflows around the Herbig Be star LkHα 234 using the Immersion Grating Infrared Spectrograph (IGRINS). Previous studies indicate that the region around LkHα 234 is complex, with several embedded YSOs and the outflows associated with them. In simultaneous H− and K−band spectra from HH 167, we detected 5 [Fe II] and 14 H 2 emission lines. We revealed a new [Fe II] jet driven by radio continuum source VLA 3B. Position-velocity diagrams of H 2 1−0 S(1) λ2.122 µm line show multiple velocity peaks. The kinematics may be explained by a geometrical bow shock model. We detected a component of H 2 emission at the systemic velocity (V LSR = −10.2 km s −1 ) along the whole slit in all slit positions, which may arise from the ambient photodissociation region. Low-velocity gas dominates the molecular hydrogen emission from knots A and 2. We newly revealed an [Fe II] jet driven by radio source VLA 3B.3. The multiple velocity peaks we observe in H 2 emission lines are consistent with a generic bow shock model. Both knots A and B show this bow shock feature. Furthermore, the positional difference (∼ 1 ′′ ) between low-and high-velocity components may be caused by a difference between the wing and apex of the bow. 4. The molecular hydrogen emission is dominant at low-velocity with a radial velocity within 50 km s −1 of the systemic velocity, while [Fe II] emission is only presnet in the higher-
We are designing a sensitive high resolution (R=60,000-100,000) spectrograph for the Giant Magellan Telescope (GMTNIRS, the GMT Near-Infrared Spectrograph). Using large-format IR arrays and silicon immersion gratings, this instrument will cover all of the J (longer than 1.1 μm), H, and K atmospheric windows or all of the L and M windows in a single exposure. GMTNIRS makes use of the GMT adaptive optics system for all bands. The small slits will offer the possibility of spatially resolved spectroscopy as well as superior sensitivity and wavelength coverage. The GMTNIRS team is composed of scientists and engineers at the University of Texas, the Korea Astronomy and Space Science Institute, and Kyung Hee University. In this paper, we describe the optical and mechanical design of the instrument. The principal innovative feature of the design is the use of silicon immersion gratings which are now being produced by our team with sufficient quality to permit designs with high resolving power and broad instantaneous wavelength coverage across the near-IR.
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