gmt instruments and ao · 2008. 5. 28. · gmt science meeting - march 2008 9 gmacs – overview...
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GMT Science Meeting - March 2008 1
GMT Instruments and AO
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Instrument Status
• Scientific priorities have been defined• Emphasis on:
• Wide-field survey science (cosmology)• High resolution spectroscopy (abundances, Doppler planets)• Adaptive optics (planets, star formation, galaxy dynamics)
• Limited imaging capability• Queue-mode operating model adopted• Eight instrument concepts have been proposed• At different levels of development• Conceptual design studies are required• Down select will occur for ~ 3 first-light instruments
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Instrument ConceptsInstrument Function λ range
(microns)Resolution FOV
GMACS
NIRMOS
Optical Multi-ObjectSpectrometer
0.35-1.0 250-4000 64-200arcmin^2
Near-IR Multi-ObjectSpectrometer
1.0-2.5 Up to ~4000 49arcmin^2
QSpec
SHARPS Optical High Resolution(Doppler) Spectrometer
0.4-0.7 150K 7 x 1” fibers
GMTNIRS
MIISE
HRCam
GMTIFS
Optical High ResolutionSpectrometer
0.3-1.05 30K1” slit
3” + fibre mode
Near-IR High-ResolutionSpectrometer
1.2- 5.0 25K-100K Single object
Mid-IR ImagingSpectrometer
3.0-25.0 1500 30”
Near-IR AO Imager 0.9-5.0 5-5000 30”
NIR AO-fed IFU 0.9-2.5 3000-5000 3”
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Adaptive Optics Modes
Mode Description FOV Resolution Instruments
GLAO
LTAO
Ground LayerAdaptive Optics
7 arcmin 0.2 arcsec NIRMOS
Laser TomographyAdaptive Optics
30 arcsec 0.01 arcsec GMTIFS,HRCam
NGSAO
ExAO Extreme AdaptiveOptics
10 arcsec 0.01 arcsec HRCam
MCAO
MOAO
Natural Guide StarAdaptive Optics
10 arcsec 0.01 arcsec MIISE,HRCAM
Multi-ConjugateAdaptive Optics
90 arcsec 0.01 arcsec TBD
Multi-Object Adaptive Optics
10/90 arcsec 0.01 arcsec TBD
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GMTNIRS
Instrument Capabilities
Wavelength (μm)1.0 10.00.3
Res
olvi
ng P
ower
5000
5000
050
0
5.0
HRCam
MIISE
GMTIFS
GMTNIRS
GMACSNIRMOS
QSpec
“Camera”
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Accommodating Wide-Field and Narrow-Field/AO Instruments
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Gregorian Instrument Mounting
• Large survey instruments mount below IP
• AO instruments - always “hot” – above IP
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GMACS – Visible Multi-Object Spectrometer
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GMACS – Overview
• Multi-object, multi-slit spectrograph• 4x spectrographs, each with blue and red arms• Field of view: 8 x 18 arcmin (~ 200 x 5 arcsec slits)• Wavelength range: 0.36 – 1.02 μm• Resolving power with 0.7 arcsec slit:
• R ~ 1400 in blue (215 km/s)• R ~ 2700 in red (110 km/s) (for accurate sky subtraction)• Cross-over at 6500 Å
• Collimated beam diameter: 300 mm• No direct imaging capability
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GMACS – Optical Design x1
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GMACS – Optical Layout x4
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GMACS – Mechanical Layout
Mask changer4 x 2 channelField lens, slit mask, pick-off
mirrors
Disperser changer
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NIRMOS – Near-Infrared Multi-Object Spectrometer
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NIRMOS – Overview
• 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 λ coverage• 5 x 7 arcmin field of view• R ~ 3000 with 0.5 arcsec slits
• Augmented by GLAO
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NIRMOS – Opto-Mechanical Layout
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GMACS/NIRMOS InterchangabilityGMACS active NIRMOS active
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Upper Instrument PlatformInstruments
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Upper Instrument Platform10 m x 16.5 m
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QSpec – Visible High Resolution Spectrometer
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QSpec – Overview
• Four beam instrument• 450 mm beam diameter• R4 echelle gratings (x2): 200 x 1600 mm• Rφ = 30,000 arcsecs• λλ = 300 nm to 1.07 µm (in four channels)• 2-pixel resolving power is R=125,000• Pupil anamorphism• White pupil design• VPH grating cross-dispersion• Four catadioptric cameras• 4k x 6.5k to 6k x 8k CCDs (with 15 µm pixels)
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QSpec – Optical design
UV: 299 to 389 nm Blue: 383 to 545 nm
NIR: 723 to 1072 nmRed: 536 to 734 nm
1 m
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QSpec on Instrument Platform
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Gravity-Invariant QSpec on C-Ring
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SHARPS – Super HARPS
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SHARPS – Overview
• Planet Doppler spectroscopy• Fiber-fed: 7x (obj, sky, cal) x 1.0 arcsec fibers• Resolving power ~ 150,000• Wavelength: > 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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SHARPS – Optical Layout
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SHARPS at Coudé Feed
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GMTNIRS – GMT Near-Infrared Spectrometer
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GMTNIRS – Overview
• Short Wavelength:• 1.2 – 2.4 μm (H & K covered in a single exposure)• Slit-limited resolving powers:
• R = 50,000, 0.3 arcsec slit ≡ 6 pixels• R3 immersion echelle grating• f/3 camera => 14 arcsec per order• 4096x4096 detector => 15 orders at K
• Long Wavelength (with AO):• 2 – 5 μm wavelength range• Diffraction-limited resolving powers:
• λ = 3.6 μm, R = 133,000, 0.06 arcsec slit ≡ 3 pixels• λ = 4.8 μm, R = 100,000, 0.08 arcsec slit ≡ 4 pixels
• f/7.8 camera => 0.85 arcsec per order at L• 2048x2048 detector
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GMTNIRS – Optical Layout
200.00mmScale: 1/8Cold pupil
paraboloid
paraboloid from GMT
paraboloidprimary
tertiary
fpa
echelle
cross-disperser
200.00 mmScale: 1/8
slit
echelle
collimator
fold
primarysecondary
FPA
tertiary
crossdisperser
Short Wavelength Long Wavelength
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GMTNIRS – Mechanical Layout
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GMTNIRS on Instrument Platform
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Adaptive Optics Instruments
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Adaptive Optics Concept
• Single DM with common wave front sensing
• Asterism of 6 laser guide stars• Variable extent on sky
• Adaptive Secondary Mirror• Straight-through path to GLAO• Dichroic folds to LTAO,
thermal NGS, & ExAO• Diffraction limit:
• 0.010 arcsec at 1.0 μm• 0.020 arcsec at 2.0 μm• 0.040 arcsec at 4.0 μm• 3x better than Gemini
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Scientific Impact of 0.016″ ImagesLTAO in the H band, 1 hr exposure, Antennae at z=1.4
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Latest AO Reimaging Concept
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AO System on Instrument Platform
LGSWFS
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MIISE – Mid-Infrared Imaging Spectrometer
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MIISE – Overview
• 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: 3-5 μm, 0.010 arcsec/pixel• Long wavelength channel: 8-25 μm, 0.030 arcsec/pixel
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MIISE – Optical Design
input fromAO feed
3-5 micron detector
8-25 micron detector
2 micronphase sensorlong wavelength
imaging channel
nulling channel
dichroic
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MIISE – Location at Direct Focus
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GMTIFS – GMT Integral-Field Spectrograph
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GMTIFS – Overview
• Single-object, AO-corrected, integral-field spectroscopy• Wavelength range: 1.0 – 2.5 μm• Resolving power: R = 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
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GMTIFS – Optical Layout
Window TelescopeFocus
Imageplane
F-converter
Pupilplane
SlicerPupil Mirror Field Mirror
Collimator
FoldGrating Camera Detector
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AO System on Instrument Platform
LGSWFS
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HRCam – High Resolution Camera
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HRCam – Overview
• Wavelength range: 1 – 2.5 μm• Sampling: 0.003 (f/46) and 0.010 (f/15) arcsec/pixel• Field of view: 13 (f/46) and 40 (f/15) arcsec• Detector: 4096x4096 pixels• Imaging:
• JHK + narrow bands• Sensitivity: Must reach H & K ~ 25 mag
• IFU spectroscopy: • 50x50 spaxels with 0.020 arcsec/spaxel• Resolving power: R ~ 3000 - 5000
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HRCam – Optical Layout
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Still to be developed…
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Optical Reimaging Camera
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Multiple Integral Field Spectroscopy
• ~ 10 IFUs• MOAO-fed• R ~ 4000• 0.1” spaxels
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Summary
• Wide range of work-house capabilities• Will it address key science in 10 yr time?• Which will be the 1st generation instruments?• Are we catering for 2nd & 3rd generation instruments?
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