Instrument Concepts

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Instrument Concepts
Instrument Function l range (microns) Resolution FOV
GMACS Optical Multi-Object Spectrometer 0.35-1.0 250-4000 36-144 arcmin2
NIRMOS Near-IR Multi-Object Spectrometer 1.0-2.5 Up to 4000 49 arcmin2
QSpec Optical High Resolution Spectrometer 0.3-1.05 30K 1 slit 3 fibre mode
SHARPS (G-CLEF) Optical High Resolution (Doppler) Spectrometer 0.4-0.7 150K 7 x 1 fibers
GMTNIRS Near-IR High-Resolution Spectrometer 1.2- 5.0 25K-100K Single object
MIISE Mid-IR Imaging Spectrometer 3.0-25.0 1500 30
HRCam Near-IR AO Imager 0.9-5.0 5-5000 30
GMTIFS NIR AO-fed IFU 0.9-2.5 3000-5000 3
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History
GMT instrument conceptual design studies
2005 Internal to GMT consortium (at that
time) GMT conceptual design review February
2006 Subsequent work by project, with partner
participation Integration of seeing-limited
instruments Reconfiguration of instrument
platform AO relay Meetings Seeing-limited
instruments workshop Adaptive optics workshop
Planet RV workshop Science with GMT (Canberra)
March 2008 Before proceeding, need to resolve
instrument-AO interface
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GMT Instrument Design Studies

• Request letters of intent (e.g. Sep 2008)
• Select list for design studies ( 6?) (Nov
  2008)
• Request for proposals released
• for each instrument (Jan 2009)
• Proposals due (Mar 2009)
• Award contracts for design studies (May 2009)
• Negotiate study contracts,
• contract start (Jul 2009)
• Finish design studies and review (Dec 2010)
• Select first light instruments,
• start instrument development (2011)

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Some Issues
Intention of design studies is to form actual
instrument teams across (and beyond) partner
institutions Design study funding project
in-kind (probably not telescope time too
sensitive) Evaluation Internal hard to avoid
some conflicts External
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GMACS

• Resolving power w/ 0.7 arcsec slit
• R 1400 in blue
• R 2700 in red
• (for accurate sky subtraction)
• cross-over at 6500 Å
• Separate 8 x 9 arcmin imaging
• channel

• Multi-object, multi-slit spectrograph
• 4x spectrographs, each with
• red and blue arms, VPH gratings
• Field of view 8 x 18 arcmin
• Wavelength range 0.36 1.02 µm
• Collimated beam diameter 300 mm

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GMACS Optical Layout x4
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NIRMOS

• Wavelength range 0.85 2.5 µm
• Imaging Mode
• 7 x 7 arcmin field of view
• 0.067 arcsec/pixel
• 6kx6k detector
• Spectroscopy Mode
• Multi-slits 140 x 3 arcsec long,
• full wavelength coverage
• 5 x 7 arcmin field of view
• R 3000 with 0.5 arcsec slits
• Augmented by GLAO

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GMACS, NIRMOS MIISE
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QSpec

• Four beam instrument
• 450 mm beam diameter
• R4 echelle gratings (x2)
• 200 x 1600 mm
• Rf 30,000 arcsecs
• ?? 300 nm to 1.07 µm
• (in four channels)
• 2-pix resolution R125,000
• Pupil anamorphism
• White pupil design
• VPH grating cross-dispersion
• Four catadioptric cameras
• 4k x 6.5k to 6k x 8k CCDs
• (15 µm pixels)

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SHARPS

• Planet Doppler spectroscopy
• Fiber-fed 7x(obj,sky,cal) x 1.0 ?
• Resolving power 150,000
• Wavelength gt 4400 6700 Å
• White pupil spectrograph design

• CCD mosaic detector
• Deep depletion CCDs for red orders
• Vacuum-enclosed spectrograph
• High-stability thermal environment
• Bulky enclosure

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MIISE Mid-IR Imaging Spectrometer

• Wavelength range 3 - 25 µm
• Field of view 30 40 arcsec
• Resolving power R 1500
• Modes
• Imaging
• Spectroscopy
• Nulling (8-25 µm)
• Coronography (3-5 µm)
• Short wavelength channel 3-5µ,
• 0.010 arcsec/pixel
• Long wavelength channel 8-25µ,
• 0.030 arcsec/pixel

3-5 µm detector
8-25 µm detector
input from AO feed
dichroic
nulling channel
2 micron phase sensor
long wavelength imaging channel
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GMTIFS GMT Integral Field Spectrograph

• Single-object, AO-corrected, integral-field
  spectroscopy
• Wavelength range 1.0 2.5 µm
• Resolving power 4000 5000
• Range of spatial sampling and fields of view
• Galaxy dynamics 0.05-0.10 arcsec sampling, 2-3
  arcsec FOV
• Black hole masses Diffraction-limited sampling,
  small FOV

Spaxel size along slit (arcsec) 0.008 0.016 0.032 0.054
Slitlet width (arcsec) 0.020 0.040 0.080 0.135
Field of view (arcsec) 0.80 1.6 3.2 5.4
F-converter
Tel focus
slicer
fold
collimator
detector
grating
camera