Giant Magellan Telescope Project
Science with Giant Telescopes - June 2008
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GMT Partners
Astronomy Australia Limited
Australian National University
Carnegie Institution of Washington
Harvard University
Smithsonian Institution
Texas A&M University
U. of Arizona
U. of Texas at Austin
Joining:
Korea Astronomy & Space Science
Institute
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GMT Project
Governing & operating bodies
• GMT Board of Directors
overall policy & governance
• Science Working Group
scientific priorities, instruments, site selection, operations
• Project Scientists’ Working Group
technical guidance, telescope and instrument design teams
• Project Office
project management, engineering, contracting, construction
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Topics
•
Telescope and related systems
•
•
•
Adaptive optics
Instrument concepts
Site selection and characterization
Pat McCarthy:
• Science priorities and capabilities
• Operations model
• Public participation
•
Status and schedule
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Telescope Concept
Seven x 1.1m
segmented secondary
mirror (3.2 m Φ)
Alt-az mount
Seven x 8.4 m segmented
borosilicate primary mirror
Laser house
Pier
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Telescope stats
Height: 38.7 meters
1,125 metric tons
Lowest Mode: 4.5 Hz
(4.3 Hz with pier)
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Operating modes
• Natural seeing operation
• 20´ “Wide-Field” mode
• Multiple AO modes
• Laser Tomography AO
(LTAO)
• Ground layer AO (GLAO)
• High contrast AO (ExAO)
• Future MCAO, MOAO
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How Big Is It?
Full Diameter: 25.4 m
Diffraction limit equivalent 24.5 m
Circular aperture 22 m
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8.4 m Primary Mirror Segments
Off-axis, highly aspheric require the development of new
casting/generating/polishing techniques
Metrology challenge
Provide multiple independent surface figure verification tests
Each mirror takes ~3.5 years
Production pipeline to produce a mirror every 10-12 months
Pacing item for GMT completion
Prototype off-axis segment to retire technical & schedule risk
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GMT1 casting
May 2005
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20082005
Jun 2005
Nov 2005
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Processing stages
Pipeline processing
1. Casting
2. Clean-out
3. Rear surface processing
a. Generating
b. Grind & polish
c. Loadspreader attachment
4. Front surface processing
a. Generating
b. Grind & polish
c. Final figuring
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Mar 2006
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SOML Polishing Lab
Test
tower
LOG
LPM
Stressed
lap
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Optical Testing
Metrology is the greatest challenge
•
High degree of aspheric departure ~14 mm
•
Requirement that segments match to high accuracy
•
•
ΔRc < 0.3 mm (0.0006%)
•
Repeatability over 10 years of production
Use compensators to relax tolerances
Principal test – full aperture, nulling interferometer
•
In-process testing during polishing
Verification Tests:
1. Laser tracker Plus test- pre-polish generation & independent loworder figure verification
2.
Scanning pentaprism- final low-order figure verification
3.
Shear test- high frequency errors
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New Test Tower
23.5 m
vertex to vertex
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M1 Fold sphere & GMT1
GMT1 Completion April 2009
GMT1
3.8 m Fold sphere
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Jan 2008
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Segmented Gregorian Secondary Mirrors
Fast-steering secondary (FSM):
Seven 1.06 m segments aligned with
primary mirror segments
Tip-tilt & translation actuators
Adaptive secondary (ASM):
Technology developed for MMT,
LBT and VLT
View from
below
~672 actuators per segment
~4700 actuators total
Capacitive position sensors.
In-telescope calibration source.
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Gregorian Instrument Mounting
Intermediate size & AO instruments always “hot” - above
Large survey instruments mount below
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AO Relay
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AO System on Instrument Platform
LGS
WFS
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Instrument Concepts
Instrument
Function
l range
Resolution
FOV
(microns)
GMACS
Optical Multi-Object
Spectrometer
0.35-1.0
250-4000
36-144
arcmin^2
NIRMOS
Near-IR Multi-Object
Spectrometer
1.0-2.5
Up to ~4000
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arcmin^2
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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“Telecentric” Corrector/ADC (20’ FOV)
BK7
ADC
Telecentrator
Exit pupil
1.53 m dia
Focal plane
BK7 & LLF6
Fused Silica
RMS polychromatic image diameter at r = 10′
uncorrected
corrected
= 0.62 arcsec
= 0.07 arcsec
Science with Giant Telescopes - June 2008
Residual dispersion @ ZD = 50º:
No ADC correction: 1.97
With ADC: 0.17
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Wide-field Corrector/ADC
Corrector
removed
M1 cell #7
ADC
Instrument Platform
Telecentrator
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GMACS
• 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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• 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
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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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Gregorian Instrument Rotator
Instrument
platform (IP)
Hydrostatic
bearings (6)
C-rings &
K-bracing
Oil
trough
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Lift platform
(not shown)
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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
• Rφ = 30,000 arcsecs
• λλ = 300 nm to 1.07 µm
(in four channels)
• 2-pix resolution: R=125,000
• Pupil anamorphism
• White pupil design
• VPH grating cross-dispersion
• Four catadioptric cameras
• 4k x 6.5k to 6k x 8k CCDs
(15 µm pixels)
Science with Giant Telescopes - June 2008
Red: 536 to 734
nm
NIR: 723 to 1072
nm
1m
UV: 299 to 389
nm
Blue: 383 to
545 nm
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SHARPS
• Planet Doppler spectroscopy
• Fiber-fed: 7x(obj,sky,cal) x 1.0” 
• Resolving power ~ 150,000
• Wavelength: > 4400 – 6700 Å
• White pupil spectrograph design
Science with Giant Telescopes - June 2008
• 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
3-5 μm detector
8-25 μm
detector
input from
AO feed dichroic
nulling channel
long wavelength
imaging channel
2 micron
phase sensor
Science with Giant Telescopes - June 2008
• 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
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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
Tel focus
F-converter
slicer
fold
collimator
detector
grating
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camera
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Sites
Science with Giant Telescopes - June 2008
Google
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Seeing Percentiles- LCO sites
Location
FWHM 25%
arcsecs
FWHM 50%
arcsecs
FWHM 75%
arcsecs
FWHM 90%
arcsecs
Manquis Ridge
0.55
0.68
0.87
1.10
Manqui Peak
(Magellan)
0.51
0.63
0.80
0.99
Alcaino Peak
0.51
0.63
0.80
1.00
Campanas Peak
0.51
0.64
0.81
1.00
Use nights suitable for observing and on which all DIMMS were operating
and operators were on site.
Reporting period: November 12, 2005 through November 19, 2007
covering all seasons.
Total nights/samples: 323/82K
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GMT Facility on Campanas Peak
Enclosure
Control Building
(Below)
Equipment Building
Facility Building
Auxiliary Building
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Prevailing
winds
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Science Drivers for the GMT
• Science
Priorities
• Operations Model
• Public Participation
• Status and Schedule
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GMT Science Drivers
Three Approaches:
Discovery Space
Synergy with Current and Future Facilities
Contemporary Science Drivers
Scientific Strengths of the GMT Design:
High angular resolution - 10mas at 1m
Large collecting area - 380 m2 - 10 x Magellan 6.5m
Wide Field - practical paths to seeing-limited survey instruments
Gregorian Adaptive Secondary - GLAO, Great mid-IR performance
Short response time for TOOs
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Discovery Space
100pc z = 1
10
100
KPC
AU
1000
100
10
10
1
0.3
0.5
1.0
2.0 3.0
5.0
10
1
0.1
20
Wavelength (m)
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Discovery Space
3
2
-
mAB
Seeing Limited
1
0
20
Adaptive Optics
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8m limit
Gain
Spectroscopy
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26
-1
GMT limit
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-2
30
-3
0.3
0.5
1.0
2.0
3.0
5.0
10
20
Wavelength (m)
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GMT SCIENCE: CONTEXT & SYNERGY
Broad Synergy Across Wavelength,
Spatial and Time Domains
JWST
Physical Diagnostics
Deep/Wide Surveys
High-resolution imaging
High SNR & Res. Spectroscopy
ALMA
LSST
SKA
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Magellan
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Complementarity with JWST
 Pic at 11m
JWST
JWST
GMT
GMT
10 AU
ALMA
GMT has 4 times the spatial resolution….
Science with Giant Telescopes - June 2008
and up to 100 times the spectral resolution
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GMT Science Goals
• Planets and Their Formation
• Stellar Populations and Chemical Evolution
• Assembly of Galaxies
• Black Holes in the Universe
• The Accelerating Universe
• First Light and Reionization of the Universe
http://www.gmto.org/sciencecase
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Updates to the GMT Science Case
New Tools:
Quantitative Science Use Cases
Exposure-Time Calculators
Spectral & Imaging Simulation Software
Examples:
• Near- and mid-IR Exoplanet Studies
D4 or faster
• AO Imaging of Resolved Stellar Populations
• Near-IR Spectroscopy of Galaxies at z ~ 2
• Ly Emission at z > 6
Science with Giant Telescopes - June 2008
GLAO &
Seeing-limited
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Exoplanets in Reflected Light
Exoplanets are faint!…
Jupiter reflects 10-9 Lsun
Earth reflects 10-10 Lsun
…and close in
Jupiter 0.5´´ @ 10pc
Earth 0.1´´ @10pc
Suppression of
diffraction is essential
Coronagraphy, phase modulation, nulling, -lensing, transits, PRV
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GMT PSF
with phase apodization
1.65 m, 5% band. Diffraction only, no
wavefront error
10-6 suppression at 4 l/D, 56 mas
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10-5 companion
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Planets and Their Formation
A handful of known exoplanets are detectable in reflection with GMT
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Mid-IR Imaging of Exoplanets
(Phil Hinz - Arizona)
L band detection limit 40x improved with ~3x
larger diameter
1 hour 5 sigma limits
3.8 um: 25 Jy
3 λ/D: 0.48”
10 um: 750 Jy
3 λ/D: 1.0”
Detect 5-10 MJ giant planets
100-300 zody warm debris
disks
3.8 um: 0.6 Jy
3 λ/D: 0.11”
10 um: 18 Jy
3 λ/D: 0.25”
Detect <1 MJ planets
3-10 zody warm debris disks
GMT can undertake comprehensive study of giant
planets in > 3 AU range around stars at 30 pc.
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Terrestrial Planets - 10 micron imaging
280K habitable planets detectable at 10m around nearby stars.
1 – 5 rE, 0.5 – 5 AU
Star
Alpha Cen A
alpha Cen B
Sirius
eps Eri
Procyon
tau Ceti
Altair
beta Hyi
Fomalhaut
d (pc)
1.35
1.35
2.64
3.22
3.5
3.65
5.14
7.47
7.69
a=280 K (AU) ang. dist. (“)
1.04
0.77
0.65
0.48
6.3
2.39
0.56
0.17
1.72
0.49
0.78
0.21
3.36
0.65
2.1
0.28
4.91
0.64
Brightness limit=25 Jy
Earth flux (uJy)
26.34
26.34
6.89
4.63
3.92
3.6
1.82
0.86
0.81
Blue is within 3 l/D
min. size (R_e)
0.97
0.97
1.91
2.32
2.53
2.63
3.71
5.39
5.55
Rocky Planets at 4 microns
600K hot rocky planets detectable at 4 m
0.1 – 1 AU, 0.14 – 1 rE
Star
Alpha Cen A
alpha Cen B
Sirius
eps Eri
Procyon
tau Ceti
Altair
beta Hyi
Fomalhaut
beta Leo
d (pc)
1.35
1.35
2.64
3.22
3.5
3.65
5.14
7.47
7.69
11.1
a=600 K (AU)
0.23
0.14
1.37
0.12
0.38
0.17
0.73
0.46
1.07
1.07
ang. dist. (“)
0.17
0.1
0.52
0.04
0.11
0.05
0.14
0.06
0.14
0.1
hot Earth (uJy)
109.74
109.74
28.7
19.29
16.33
15.01
7.57
3.58
3.38
1.62
mini. size (R_e)
0.14
0.14
0.26
0.32
0.35
0.37
0.51
0.75
0.77
1.11
Brightness limit=2 Jy
AO Imaging of Resolved Stellar Systems
Globular Cluster around Cen A
HST
3.8Mpc
Gemini
3pc core radius
H-band
GMT
4mas pixels
2
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AO Imaging of Resolved Stellar Systems
Globular Cluster around Cen A
Gemini
3.8Mpc
3pc core radius
H-band
GMT
See Knut Olsen’s chapter in the GSMT book
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Operations Philosophy
Use observing time as efficiently as possible (“Flexible”)
• Provide technical expertise during observations
• Use best conditions most effectively
• Be able to switch programs and instruments quickly
• Enable time-critical observations
Retain benefits of on-site PI’s where practical (“Assisted”)
• Guest observers interact with instrument, data & staff in real time
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Observing Modes
• Semi-Classical PI observing
• Block-scheduled time, PI/team present and may run instrument
• Best for large programs or campaigns
• Remote PI observing
• Block-scheduled time, PI/team remote (video link)
• Queue-scheduled service observing
• Observatory staff execute a queue of observations as appropriate
for the conditions. Preferred mode for TOO & synoptic
Projected Staffing Level
• 120 FTEs split between Chile (86) and the US (34)
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Science & Data Archives
• Baseline operations plan includes only bare-bones
archive - “save the bits”++, NVO compliance etc .
• Pipeline software expected to be part of instrument
contracts, maintained by the observatory.
• Community input sought on issues relating to valueadded features, high-level data products, interfaces.
Issues:
Proprietary period, costs, role of national centers, NVO,
international partners participation
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Public Participation in GMT
How much time could be available through federal participation?
25-30% NSF share ~ 80 - 100 nights
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Public Role in GMT
What role can AURA & the community play in the development of GMT?
• Instrument development and selection
• Conceptual development
• Science teams associated with instruments
• Input into selection priorities
• Operations planning
• Operational models
• Refined cost planning
• Definition of archive and other value-added products
• Participation in planning and execution of large science programs
• Development of PI-level science projects
GMT Public Policy White Paper: www.gmto.org/overview
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Instrument Selection Timescale
Call for new and continuing concept studies
Winter 07/08
Design reviews
Fall 2010
Selection of first generation instruments
Fall 2010
Second generation instruments defined
Mid 2012
First instruments delivered to Chile
Fall 2016
There remains time and opportunity for the community to be engaged in
the instrument development and selection process
GMT is open to considering complementarity with TMT in first & second
generation instrument suites
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Legal Niceties
The GMT Founder’s Agreement:
Defines organizational structure
Determines governance procedures
Specifies how $$
access
Transfers responsibility to the GMTO Corp.
The GMTO Corporation
A not-for-profit company
Will assume responsibility for the project
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Status and Schedule
You are here
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