Instrumentation progress at the Giant Magellan Telescope project

Abstract

Instrument development for the 24m Giant Magellan Telescope (GMT) is described: current activities, progress, status, and schedule. One instrument team has completed its preliminary design and is currently beginning its final design (G-CLEF, an optical 350-950 nm, high-resolution and precision radial velocity echelle spectrograph). A second instrument team is in its conceptual design phase (GMACS, an optical 350-950 nm, medium resolution, 6-10 arcmin field, multiobject spectrograph). A third instrument team is midway through its preliminary design phase (GMTIFS, a near-IR YJHK diffraction-limited imager/integral-field-spectrograph), focused on risk reduction prototyping and design optimization. A fourth instrument team is currently fabricating the 5 silicon immersion gratings needed to begin its preliminary design phase (GMTNIRS, a simultaneous JHKLM high-resolution, AO-fed, echelle spectrograph). And, another instrument team is focusing on technical development and prototyping (MANIFEST, a facility robotic, multifiber-feed, with a 20 arcmin field of view). In addition, a medium-field (6 arcmin, 0.06 arcsec/pix) optical imager will support telescope and AO commissioning activities, and will excel at narrow-band imaging. In the spirit of advancing synergies with other groups, the challenges of running an ELT instrument program and opportunities for cross-ELT collaborations are discussed.

Adaptive Optics for Extremely Large Telescopes

“…Both, the wide-¯eld optical multi-object spectrograph GMACS (DePoy et al, 2012) and G-CLEF will bene¯t from the GMT's ground-layer AO observing mode van Dam et al, 2014). The near-infrared integral¯eld spectrograph and imager GMTIFS (Sharp et al, 2016) and the nearinfrared high-resolution spectrograph GMTNIRS (Ja®e et al, 2016;Jacoby et al, 2016) will use the GMT's laser tomography AO system van Dam et al, 2016). An overview of all three telescopes, their AO type, and their planned¯rst suite of instrumentation is given in Table 1.…”

“…For the GMT, the suite of ¯rst-light instruments (Jacoby et al, 2016) using AO consists of a ¯berfed, cross-dispersed echelle spectrograph able to deliver precision radial velocities to detect low-mass exoplanets around solar-type stars, hence the name of the instrument GMT-consortium large earth ¯nder G-CLEF (Szentgyorgyi et al, 2016). Both, the wide-¯eld optical multi-object spectrograph GMACS (DePoy et al, 2012) and G-CLEF will bene¯t from the GMT's ground-layer AO observing mode (Bouchez et al, 2014;van Dam et al, 2014).…”

Novel gratings for astronomical observations

“…The echelle spectrograph in which spectrum is folded on to a photographic plate or a 2-dimensional imaging detector, combines a high-order diffraction grating with a prism or a diffraction grating with low angular dispersion as a cross disperser. In the reasons, a transmission grating of echelle type with large angular dispersion and with high diffraction efficiency is required for an astronomical spectrograph of a large telescope such as the TMT (Thirty Meter telescope), the 8.2m Subaru Telescope [1][2][3][4][5][6][7]. Propagation of incident beam in SR transmission grating with sawtooth shape ridges (left), diffraction efficiency versus lattice period normalized by peek wavelength (middle) [2,7,8] and grisms (direct vision grating) for FOCAS (right).…”

Thirty Meter Telescope science instruments: a status report

“…Table 2 shows the equivalence between the GMT, TMT and E-ELT suites 22,23 . This is not a one-toone mapping, but it does show how they overlap and differ.…”