Instrumentation Concepts for the 30-meter GSMT

1. Instrumentation Concepts for the 30-meter GSMT S.C. Barden, M. Liang, K.H. Hinkle, C.F.W. Harmer, R.R. Joyce (NOAO/NIO) September 17, 2001

2. GSMT Point Design Instrument Study • Develop telescope, AO and instruments as an integrated system • Design concepts driven by science objectives • Multi-Object, Multi-Fiber, Optical Spectrograph MOMFOS (science: tomography of the universe) • Near IR Deployable Integral Field Spectrograph NIRDIF (science: tomography of pre-galaxy fragments) • Mid-IR, High Dispersion, AO Spectrograph MIHDAS (science: origins of planetary systems) • MCAO-fed near-IR imager (science: stellar populations) • Build on extant concepts where possible • Define major design challenges • Identify needed technologies

3. Multi-Object Multi-Fiber Optical Spectrograph (MOMFOS) • 20 arc-minute field at f/1 Prime Focus • 60-meter fiber cable • 700 0.7” fibers • 3 spectrographs, ~230 fibers each • VPH gratings • Articulated collimator for different resolution regimes • Resolution Example ranges with single grating • R= 1,000 350nm – 650nm • R= 5,000 470nm – 530nm • R= 18,000 491nm – 508nm • Detects 13% - 23% of photons hitting the 30m

4. Prime Focus MOMFOS

5. MOMFOS with Prime Focus Corrector Conceptual design fits in a 3m dia by 5m long cylinder

6. MOMFOS Spectrograph Micro-Lens Relay 100% of light couples into fiber. 500 mm diameter fiber fed by two micro-lenses with spherical surfaces. Field stop limits light to 0.72” aperture. Comparable lens required at fiber output.

7. MOMFOS Spectrograph Fiber Positioner Positioner based on Echidna positioner built by AAO for FMOS on Suburu Echidna prototype image from www.aao.gov.au/local/www/echidna/

8. R=18000 mode R=5000 mode R=1000 mode 500mm pupil; all spherical optics MOMFOS Spectrograph 3 Spectrographs 230 fibers each f/4.5 Collimator f/0.86 Camera 10 VPH gratings to cover full optical range and 3 resolution modes. Articulated collimator 4K by 4K CCD 15 mm pixels 2 pixel binning

9. MOMFOS Spectrograph Predicted Efficiency

10. On-Axis Fiber Diameter Half-Field Full-Field Spot Diagrams for MOMFOS Spectrograph R = 5000 1126 l/mm 794-904 nm 28.6°

11. Tomography of Individual Galaxies out to z ~3 GSMT 3 hour, 3s limit at R=5,000 0.1”x0.1” IFU pixel (sub-kpc scale structures) J H K 26.5 25.5 24.0

12. Near Infra-Red Deployable Integral Field Spectrograph (NIRDIF) • MCAO fed • 1.5 to 2.0 arc-minute FOV • 1 – 2.5 mm wavelength coverage • Deployable IFU units • 1.5 arc-second FOV per IFU probe • 31 slices per IFU probe (0.048” per slice) • ~26 deployable units

13. Near Infra-Red Deployable Integral Field Spectrograph (NIRDIF) Relay optics contained in deployable arm. 1.5 by 1.5 arc-second field of view. f/38 to f/128 converter from MCAO field to image slicer. Telecentric input and output. Cold stop located within relay.

14. Near Infra-Red Deployable Integral Field Spectrograph (NIRDIF) f/128 image slicer with 31 slices converted to f/11.5 for the spectrograph. • Spectrographs • 2 IFU’s per spectrograph • ~13 spectrographs • R = 1000 to 10,000 • Z, J, H, and K spectral coverage • 2 K detector format assumed

15. Near Infra-Red Deployable Integral Field Spectrograph (NIRDIF) Image Slicer Image Relay Spectrograph Two Image Slicers per Spectrograph

16. Slice 1 Slice 16 Slice 31 Near Infra-Red Deployable Integral Field Spectrograph (NIRDIF) Spot diagrams for NIRDIF spectrograph.

17. Origins of Planetary Systems • Goals: • Understand where and when planets form • Infer planetary architectures via observation of ‘gaps’ • Measurements: Spectra of accreting PMS stars (R~105; l ~ 5, 17 mm) • Key requirements: On axis, high Strehl AO; low emissivity

18. Mid-Infrared High Dispersion AO Spectrograph (MIHDAS) • Adaptive Secondary AO feed • On-Axis, Narrow Field/Point Source • R=120,000 • 3 spectrographs • 2-5 mm (small beamed, x-dispersed), 0.2 arc-second slit length • 10-14 mm (x-dispersed), 1 arc-second slit • 16-20 mm (x-dispersed), 1 arc-second slit • 10-14 mm spectrograph likely to utilize same collimator as 16-20 mm instrument. Different Gratings and Camera. • 2-5 mm spectrograph may require additional AO mirrors.

19. Mid-Infrared High Dispersion AO Spectrograph (MIHDAS) 16-20 mm spectrograph will be large. Diffraction limit at 20 microns is about ¼ arc-second, comparable to native seeing limit. Echelle grating is 1.5 meters in length! Overall instrument is expected to take up a volume of about 4 by 2 by 3 meters! All of which needs to be cryogenically cooled. Instrument to be located at Cass location and move with the telescope.

20. Mid-Infrared High Dispersion AO Spectrograph (MIHDAS) f/18.75 Collimator f/2 Camera 150 mm by 1500 mm R10 (84°) Echelle 7 mm/line (0.143 l/mm) 360 mm diameter cross-disperser 45 l/mm, 26.5° blaze Off-axis parabolic collimator 4-mirror camera 1K by 1K Si:As detector 27 mm pixels

21. MCAO Near-IR Imager • f/38 input with 1:1 reimaging optics • 1.5 to 2 arc-minute field of view • Monolithic imager - • 5.5 mm/arc-second plate scale! • 0.004 arc-second per pixel sampling • 685 mm sized detector array for 2 arc-min field! • 28K by 28K detector! • 7 by 7 mosaic of 4K arrays Alternative approach is to have deployable capability for imaging over a subset of the total field.

22. Instrument Locations on Telescope Fiber-fed MOMFOS MCAO-fed NIRDIF or MCAO Imager Cass-fed MIHDAS

23. Information on AURA NIO activities is available at: www.aura-nio.noao.edu