Giant Magellan Telescope Project Science Drivers & AO Requirements

AO4ELT - Paris 2009 1

Giant Magellan Telescope Project

Science Drivers & AO Requirements

Patrick McCarthy - GMT Director

Phil Hinz & Michael Hart - GMT AO TeamAO4ELT - June 22, 2009


The GMT Partners

US Institutions

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Space Science Institute


The GMT Concept

Giant-Segmented Mirror Telescope

10mas @ 1μm380 sq. meters

f/8 Gregorian

Segmented Adaptive Secondary

Natural Seeing 20 FOV

Ground-Layer Correction 8 FOV

Diffraction-limited 20- 40 FOV


Gregorian Instrument Mounting

Survey, GLAO, & Mid-IR instruments below

LTAO instruments above


Instrument Platform Top Layout

Natural seeing instruments

AO relay

AO instruments GLAO/LGS

wavefront sensors

10 m

16 m


Gregorian Instrument Rotator

GLAO & Mid-IR

Instruments

Instrument platform (IP)

Multiple instrument mounting


Instrument Development

GMT Instrument Concepts Modeλ specification

(microns)

High resolution near-IR camera LTAO 1.0-2.5

High contrast Mid-IR AO imager NGSAO 1.2-2.5 & 3-5

Near-IR echelle spectrograph AO & NS 0.9-5

High resolution optical spectrometer NS 0.34-0.90

Wide-field multi-object near-IR spectrograph GLAO 1.2-2.5

Wide-field multi-object optical spectrograph NS 0.34-0.9

Near-IR integral field spectrometer LTAO 1 – 2.5

Mode: AO = adaptive optics, NS = natural seeing

NIRMOS GMTNIRS GMACS


AO Science Drivers

Exoplanet Studies

Imaging exoplanets in reflected light

Thermal radiation from young exoplanets

Structure of debris disks

Stellar Populations

IMF variations

Star Formation Histories

Black Hole Demographics

Galaxy Assembly

Structure & Dynamics of Galaxies at z > 2

First Light Studies


L band detection limit 16x improved with ~4x larger diameter

• 3.8 um: 25 Jy 10 um: 750 Jy• 3 λ/D: 0.48” 3 λ/D: 1.0”

• 3.8 um: 1.5 Jy 10 um: 45 Jy• 3 λ/D: 0.11” 3 λ/D: 0.25”

• Detect 5-10 MJ giant planets• 100-300 zody warm debris

disks

• Detect <1 MJ planets• 3-10 zody warm debris disks

1 hour 5 sigma limits

Mid-IR Imaging of Exoplanets

GMT can undertake comprehensive study of giant planets in > 3 AU range around stars at 30 pc.

HR8799 MMT


Nascent Planetary Systems

JWST

GMT

ALMA

JWST

GMT

10 AU

Pic at 11m

Gemini

ELTs have the spatial resolution to probe the zone where Earth-like rocky planets live


Globular Cluster around Cen A 3.8Mpc 3pc core radius H-band

HST Gemini GMT

24mas pixels

Laser Tomography Adaptive Optics

Resolving Distant Stellar Systems with AO


Resolving Distant Stellar Systems with AO

Gemini 8m

GMT 25m

Globular Cluster around Cen A 3.8Mpc 3pc core radius H-band


UDF 6462, H-band, NIFS, Hαz = 1.57, MB = -21.0, 5 hr object, 5 hr sky

HUDF - i

NIFS - Sum

Clump cluster


UDF 6462, H-band, GMTIFS, Hαz = 1.57, MB = -21.0, 5 hr object, 5 hr sky

HUDF - i

GMT - Sum

Clump cluster


Image Sharpening with GLAO

15 x 15

60 mas pixels

0.5 FWHM 0.15 FWHMThe GMT architecture is ideally suited for Ground-Layer AO

Native Seeing GLAO


Adaptive Optics Prioritization

Three guiding considerations:

1. The AO system should allow us to meet our science goals

2. It should build on the natural strengths of the GMT

- low thermal IR foot print

- ground-layer conjugation with wide-field of view

- clean diffraction pattern

3. A clear upgrade path that uses much of the first generation hardware


AO Science Targets

Targets Requirements

Exoplanets, debris disks, Diffraction-limited images & IFU Spectra

AGN, black holes small sizes, low sky density, no multiplexing

High Strehl, small field, low-background - Laser Tomography (LTAO) & NGS AO

z > 2 galaxies Range of sampling scales, IFU & slit spectra

small sizes, moderate sky density

All-sky, range of Strehl, range of field, near-IR only - GLAO & LTAO

Resolved stellar populations Diffraction-limited, emphasis on photometry

range of sizes, low sky density

All-sky, high Strehl, large field - LTAO & MCAO


Mode Description

Laser tomography AO(LTAO)

“All-sky” high Strehl - Sodium beaconsadaptive secondary is DM

Ground Layer AO(GLAO)

“All sky” - Sodium beaconsfactor of 2-4 image size reduction, 9′ FOV

Adaptive secondary conjugates to ground-layer

Natural Guide Star AO (NGSAO)

High Strehl - natural guide stars within the isoplanatic patch

Multi-Conjugate~1′ diameter field, diffraction-limited, uniform PSF

12km conjugate DM in AO relay

Extreme AO(ExAO)

High contrast, high Strehl for exoplanet detection tweeter DM in instrument

First Generation GMT AO Modes

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AO Features Unique to the GMT

• ASM allows low background observations at > 2 µm.• For 25 m telescope, AO correction is needed even at 10

microns.• Exoplanet imaging and planet formation science drivers

are strengthened by this design choice.

• ASM and wide-field telescope design enables GLAO.• Will increase the sensitivity and resolution of the planned

multi-object NIR and visible spectrographs for GMT.• Galaxy assembly and high-z science drivers are

strengthened by this design choice.

GCAR, Pasadena CA, April 27-29, 2009 -- AO system 20

System Performance

• System is designed to maximize science return with minimal technical development:

• Adaptive Secondary Mirrors are near-replicas of LBT, VLT design

• Laser Guide Star system builds on Na laser development for current telescopes.

• Laser Projection system is similar to MMT design.• Expected AO performance is similar to MMT/LBT

systems.

• Within the technical constraints above, the system performance and design is derived from the science requirements and the science instrument needs.

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AO System PerformanceWavefront error source RMS wavefront error (nm)

NGS LTAO ExAO

Primary mirror figure 20 20 15

Secondary mirror figure 20 20 15

Piston anisoplanatism (1 min calibration) 25 25 0

Piston errors from primary edge sensors 25 25 25

AO optical train (non-common path) 18 21 0

Science instrument 20 20 7

Fitting error 121 121 80

Atmospheric temporal lag 93 93 61

WFS measurement noise propagation 83 28 50

Reconstruction error 52 95 0

High order total 189 190 117

Anisoplanatism error 260 @13″ 148 @ 1' 0

Residual windshake 50 50 30

Total: On-axis 196 196 121

Total: Off-axis 325 @ 13″ 246 @ 1′

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AO System Performance

NGS performance versus guidestar brightness

1 ms 2 ms

10 ms

5 ms

AO System Performance versus wavelength

SJ = 36%

SH = 56%

SK = 72%

SL’ = 90%SM = 94%

Wavelength (µm) V magnitude (K5 star)K

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GMT 8.4m Off-Axis Prototype

The first GMT primary segment is in the polishing/figuring stage

Completion date: March 2010

GMT Segment #1

at the Steward

Observatory Mirror Lab


Schedule

Astronomical Society of Australia Meeting - Perth July 08 26

GMT’s AO Top-Level Requirements Play to its Strengths:

Mid-IR with Adaptive Secondary

Wide-field Ground-Layer AO

Laser Tomography

Seeing-Limited Requirements and Instruments are also important…

High Dispersion Spectrographs

Wide-field Multi-Object Spectrographs

Backup Slides


Adaptive Optics Prioritization

GMT First Generation AO Modes:

- “all sky” laser tomography AO

high Strehl, 20 - 40 field of view, depending on

- Ground layer adaptive optics

8 diameter field, factor of 2 - 4 improvement in FWHM, EE

- Natural guide star AO

high Strehl, small field of view, low thermal IR background

Upgrade modes:

MCAO (2nd DM in AO relay) ExAO (2nd DM in instrument)


L band detection limit 40x improved with ~3x larger diameter

3.8 um: 25 Jy 10 um: 750 Jy3 λ/D: 0.48” 3 λ/D: 1.0”

3.8 um: 0.6 Jy 10 um: 18 Jy3 λ/D: 0.11” 3 λ/D: 0.25”

Detect 5-10 MJ giant planets100-300 zody warm debris

disks

Detect <1 MJ planets3-10 zody warm debris disks

1 hour 5 sigma limits

Mid-IR Imaging of Exoplanets

GMT can undertake comprehensive study of giant planets in > 3 AU range around stars at 30 pc.


AO Imaging of Young Planets

8m

Angular Separation (mas)

2/D at 1.5m

42m30m25m

8m


AO System Layout

LGS Projector

Laser beam relay

Laser house

Adaptive secondary mirror (ASM)

AO Focal Plane Assembly (FPA)

• Optical relay

• LGS wavefront sensors

• Phasing camera

• AO instruments

top view


AO System Overview

Laser Housing

AdaptiveSecondary Mirror(~4700 actuators)

Laser Projector

AO relay andNarrow-field WFS

GLAO WFS

top view


Three independent measurements

Principal optical testFull-aperture, interferometric test

Scanning pentaprism testMeasures low-order aberrations

via slopes

Laser Tracker PlusScans surface with laser tracker

Works on ground or polished surface


Phase Apodization

1.65 m, 5% band. Diffraction only, no wavefront error

10-6 suppression at 4 /D, 56 mas

10-5 companion


AO Imaging of Massive Planets


3/D at 1m

8m

25m30m42m

Log

Con

tras

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AO Studies of Black Hole Demographics

8m

GMT

1.22/D

@1.5m


AO Imaging of Young Planets

8m


2/D at 5m

GM

T

8m

Giant Magellan Telescope Project Science Drivers & AO Requirements

Documents

ir cameraltao1

ir spectrographglao1

hr object

instrument developmentmode

jy10 um

ir echelle spectrographao

pc core radius hbandao4elt

fwhmthe gmt archi