Wendy Freedman Carnegie Observatories

Chair, GMT Board

Texas A&MMitchell Symposium

April 12, 2006

The Giant Magellan Telescope

The Giant Magellan Telescope (GMT)

www.gmto.org

GMT DesignAlt-az telescope structure

Seven 8.4-m primary mirrors

• 24.5-m diffraction equivalent

• 21.5-m equivalent aperture

GMT Institutions

• Carnegie Observatories• Harvard University

• Smithsonian Astrophysical Observatory

• Texas A&M University

• University of Texas, Austin• University of Arizona• University of Michigan• Massachusetts Institute of

Technology

• + …OTHERS TBD

The GMT

• Why this group of institutions?

More than 300 years of telescope building

experience within the consortium

Last telescope came in under budget

GMT Project Scientists Working Group

• Steve Shectman Carnegie Observatories

• Roger AngelU. Arizona

• Dan FabricantHarvard/Smithsonian CfA

• Phillip MacQueenU. Texas at Austin

• Rebecca BernsteinU. Michigan

• Paul SchechterMIT

• Matt JohnsCarnegie Observatories

•Charles JenkinsAustralia

Science Working Group• Warrick Couch

Australia

• Xiaohui FanArizona

• Karl GebhardtTexas

• Gary HillTexas

• John HuchraHarvard

• Scott KenyonSmithsonian

• Pat McCarthy (chair)Carnegie

• Michael MeyerArizona

• Alycia WeinbergerCarnegie/DTM

Telescope Structure & Optics

Height = 43 meters

Rotating: 961 tons

7 x 8.4m Primary mirror segments

+ 1 spare off-axis segment.

Windshake: 4.5Hz lowest structural modes

The mirrors

Mold assembly for GMT Mirror 1

Machine and install 1681 ceramic fiber boxes in silicon carbide tub.

Tops of boxes follow shape of aspheric surface; no two are identical.

Loading the Glass

Close furnace: melt and spin.

Inspect, weigh, and load 18 t of E6 borosilicate glass.

Casting First Off-Axis Segment: July 2006

First GMT off-axis segment

Heat to 1160˚C, spin at 4.9 rpm, hold 4 hours to allow glass to fill mold. Cool rapidly to 900˚C then slowly for 3 months, 2.4 K/day through annealing (530-450˚C).

Lift and washout

Tilted into vertical planeRear surface with floor tiles

attached

Segment with lifting fixture

Removal of floor tiles

Stressed Lap Polishing Machines at SOML

LOGTest tower

Stressed lap

New test tower at Mirror Lab

* Needed for 8.4 m

off-axis segments

* Long 36 m radius of curvature (LBT = 20 m)

* Requires diffraction limited 4 m folding spherical mirror at top

Segmented Adaptive Gregorian Secondary Mirror

Technology developed for MMT & LBT

7 Segments aligned with Primary mirror segments attached to a single reference body.

~672 actuators per segment

~4700 actuators total64 cm MMT AO secondary mirror

GMT Secondary Mirrors

Baseline Adaptive Optics Modes

1) Ground Layer AO covering 8′ diameter field at the direct Gregorian focus (0.9-2.5 μm)

2) Laser Tomography AO providing high-Strehl, diffraction-limited correction across a 1′ to 4′diameter field at folded Gregorian focii on the instrument platform (0.9-2.5 μm)

3) Extreme Contrast AO optimized for the detection of planetary disks and young, hot planets with dedicated instruments on the instrument platform

Scientific Impact of 0.016″ Images:LTAO in the H band

First Generation Instrument ConceptsInstrument λ(μm) Resolution FOV Modes

Visible WF MOS

0.4 -1.0

500-5000 60-150�′ MOS, Imager

NIR MOS 0.9 -2.5

1500-5000 25-100�′ MOS/IFUImager

Visible Echelle

0.3 -1.0

20K -100K

20′′ Single Object Fiber feed

NIR Echelle 1 - 5 50K-150K 30′′ Single Object

MIR AO Imager

3 - 25 5-3000 2′ x 2′ Coronagraph Nulling int.

NIR AO Imager

1 - 2.5 5-5000 30′′ ``Wide-field’’ & high definition modes

GMT Instrument Platform (IP)

RotatorGLAO Guider

Folded portinstruments

Gregorianinstruments

capacity6.4 m Dia.7.6 m high

25 ton

Optical MOSNear-IR MOS

Mid-IR Spectrograh

EchelleAO imager

Carousel Enclosure

C. Hull

60 m

54 m

Enclosure Structure

M3 Engineering

Site Testing

Northern Chile sites• GMT conducting tests at 4 LCO sites

• Coordinate/share data with other

projects

Test equipment• Differential Image Motion Monitors

(DIMM)

• Meteorological stations

• Multi-aperture Scintillation Sensor

(MASS)

• All-sky camera

• Precipitable Water Vapor

Magellan (Manqui) Campanas Pk.Alcaino Pk.

Ridge (Manquis)

Light PollutionCalculation of light pollution based on satellite imagery obtained in 1996-1997. Lowest contours indicate 1-10% increase over natural sky brightness

Source: http://www.lightpollution.it

Examples of MASS/DIMM Data

Phillips

Science with the Giant Magellan Telescope

Key Science Areas

• The First Stars and Galaxies

• Nature of Planets beyond our Solar System

• New Discoveries

www.gmto.org

Complementarity with JWST

JWST

GMT

JWST

GMT

10 AU

β Pic at 11μm

GMT has 4 times the spatial resolution…. and up to 100 times the spectral resolution

McCarthy

Origin and Evolution of Galaxies and Structure in the Universe

1. First light and reionization

2. Assembly of galaxies and clusters

3. Energetics of the IGM

4. Origin of the Hubble Sequence

CMB (WMAP image): seeds ofgalaxy and LSS formation

Sloan z > 6 quasar

Galaxy Assembly & First Light

With its wide field of view and enormous collecting

area GMT will:

• Probe star formation in the first billion years of cosmic time

• Gauge the formation of galaxies via the buildup of mass & heavy elements

• Explore the connection between galaxies and the intergalactic medium

He II 1640 emission-line Image in H-band

Numerical simulation

Star formation at z = 10 with GMT

Barton et al. 2005

Z = 6 with GMT

Simulated 15 hr integration AΩ = 10 x DEIMOS

Galaxies and the IGM

Simulated GMT spectrum of R = 24 galaxy at z = 2.4

Origins of Stars and Planets

1. What determines stellar, brown-dwarf and planet mass functions?

2. Environmental influence on planet formation process

3. Evolution from proto-planetary disks to planetary systems

Circumstellar debris disk

Radial velocity detection of planets

Large segments enable detection of extra-solar planets in reflected light

Physical Properties of Extra-Solar Planets

1. Physics of planetary atmospheres

2. Survival of “hot Jupiters”

3. What are the distributions of planetary temperature, albedo, mass, size?

Nulling interferometry at 10 μ m with Magellan

Model spectra of giant planets

GMT nullinginterferometry

GMT direct imaging

Planets and Their Formation

With its superb angular resolution & sensitivity

GMT will:

• Image known exoplanets in reflected light

• Discover young massive planets in nearby star forming regions

• Probe the structure of proto-planetary gas and debris disks

Can GMT carryout the NAS Decadal Survey Science case?

Yes! Some parts take ~30-50% longer, others may be faster than the nominal GSMT

What unique capabilities are offered by GMT?- Adaptive optics at the secondary- A unique PSF that is well suited to ExAO- Rapid instrument changes/TOO access- Wide-field GLAO - Wide-field spectroscopy without fibers

Schedule Milestones

Contract for 1st primary mirror segment 2004

Cast 1st segment 2005

Complete conceptual design (review) 2006

Complete Preliminary Design (reviews) 2008/9

Complete 1st segment 2008

Construction Phase Starts (assuming funding) 2009

First Light with 4 segments 2013

First science operation 2015

All 7 segments installed 2016

Toward Realizing the GMT

• Where are we now?

First primary mirror cast successfully in July

Conceptual Design completed

Conceptual Design Review of Project February

STRONG RECOMMENDATION TO PROCEED TO DDP!

Beginning Polishing/Testing phase of Mirror I.

Fundraising for Detailed Design in progress

Stay tuned … !