Extremely Large Telescopes Isobel Hook University of Oxford

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Extremely Large TelescopesIsobel HookUniversity
of Oxford
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OPTICON ELT Science Working Group

• OPTICON activity under EU FP5 FP6
• Over 100 volunteers
• Open to all
• Parallel to Design Study
• Recent meeting Florence, Nov 2004

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ELT Projects N. America
CELT
GSMT
Giant Magellan Telescope GMT (21m)
TMT Thirty Meter Telescope
VLOT
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ELT Projects - Europe
Euro-50
VLT UT1
OverWhelmingly Large (OWL)
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Science with a 50-100m telescope
Planets orbiting other stars Star formation history across the Universe
Planetary environments of other stars Dark Matter
Solar system planetary weather Dark Energy
Solar system complete census of small bodies First objects and the reionisation of the Universe
Resolved stellar populations High redshift intergalactic medium
Massive Black Holes demography
THE UNEXPECTED
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Our Solar System
Equivalent to flotilla of spacecraft Repeat
observations
Object Surface Resln (km) Pixels across typical disc Notes
Moon 4m 106 Illustrative
Mars 2 3400
Asteroids 3-7 200 Ceres, Vesta
Jupiter 8 500 moons
Saturn 15 300 Titan
Uranus 30 25 Ariel
Neptune 45 90 Triton
Pluto 60 90
Varuna 63 15 Large TNO
Assuming 100m telescope diffraction limit at 1mm
Jovian Satellite Io
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ELT terrestrial planet studies are we alone?
Candidate Hot Giant Exo-planet observed with
VLT/NACO (Sep 04)

• 30m telescope can observe mature gas-giant
  exo-planets to 10-20pc
• To study exo-earths, need
• large sample (1000 stars)
• to reach 30pc
• resolution (33mas)
• contrast 1010
• gt50m
• Want to obtain
• Spectroscopy gt O2, H2O
• Orbits
• Whole systems

GQ Lupi b Neuhauser et al (Apr 05)
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Planet detection models for OWLO. Hainaut and R.
Gilmozzi

• Simulated eX-AO-corrected psf
• Spectra of Sun, Jupiter, Earth
• Sky
• OWL efficiency simulator
• Photon noise
• cophasing errors

Filter R, t 10ks strehl0.5 d 10pc,
D100m Jupiter S/N80 Earth S/N10
100m may detect Earth to 25pc Spectroscopy to
about 15pc
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Factors affecting contrast

• Now have quantitative estimates/ simulations - or
  requirements on control for
• Seeing speckles (differential imaging)
• Scintillation
• Piston errors (static non-static)
• Coronography
• Wavelength difference between WFS and science
• Non common-path WF errors

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Planets and Stars

• Giant planets
• Moons
• Rings
• Planetary disks
• gaps
• Low-mass (planetary?) objects
• Jets, outflows

Simulation of planetary disk formation Lucio
Mayer
HST image of Eta Carinae -Morse Davidson, NASA
Gemini observations of the Orion nebula - Lucas,
Roche Riddick (2003)
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Resolved Stellar populations and Galaxy Formation

• Measuring age chemical composition of
  individual stars gt merger history
• Colour-mag diagram reveals multiple stellar pops
• Currently limited to MW and its satellites
• 30-m telescope could extend this to other
  galaxies in LG e.g. M32
• What about a representative slice of the
  Universe?
• Need 100m to reach Virgo
• Overcome crowding
• Collecting area

Aparicio and Gallert (2004)
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Resolved stellar populations -II

• Spectroscopic observations give dynamics (eg CaT)
• Intemediate-res measures metallicity indicators
• High-res spectroscopy gives abundances
• Simulations needed to set requirements on
• PSF shape
• Stability (temporal and spatial across field)
• Optimal wavelength

Figure credit Paul Harding
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Black Holes

• ELT can resolve sphere of influence of Black
  holes at large distances from us
• E.g. a 100m telescope at diffraction limit can
  resolve
• 104 Mo BH out to 10 Mpc from us
• Supermassive 109 Mo BH at all redshifts (where
  they exist!)

Artists conception of an AGN (GLAST/NASA)
M. Hughes et al
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Evolution of galaxiesPhysics of galaxies 1ltzlt5

• Goal to understand formation of galaxies
  feedback processes (SNe, AGN)
• Want to spatially resolve on kpc scales
• Star formation history
• Stellar mass
• Extinction
• Metallicity
• Ionisation state
• Line shapes (gt winds)
• Internal dynamics
• Relate this to galaxy haloes

Velocity fields of distant galaxies from GIRAFFE
Integral-field Unit observations (Flores et al
2004)
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Evolution of GalaxiesAssembly of galaxy haloes

• Map evolution dark matter from 1ltzlt5
• Understand effects of merging and feedback
  processes
• Want to measure
• kinematics within large galaxies
• kinematics of satellites
• lensing of background objects (halo masses)

Evolution of dark matter in a galaxy halo- Abadi
et al 2003
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Evolution of galaxies Requirements

• Similar for galaxies haloes
• Multiple IFUs 2 types
• 10 with 2x2
• 100 with 0.5x0.5
• R 5000-10000
• 0.5-2.5mm
• (goal 0.3-2.5mm)
• AO system for resolved studies (0.01-0.05)
• FOV gt2 (10 goal)
• 1 night per field with a 100m

FALCON concept (Hammer et al)
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The First Galaxies

• z 6-7 galaxies have been found
• Higher-z must exist
• Old populations seen at z6
• Z6 QSOs imply massive galaxies at earlier epochs
  
• Universe is ionised by something!
• Find by imaging
• Use JWST to find candidates?
• Probably too faint for JWST continuum
  spectroscopy
• 60m could reach mH29 in 100hrs (depending on
  source size)
• Spectroscopy at zgt10 hard even for 100m

The Universe at z6.1 (Gnedin 2000) Neutral H,
ionising intensity (z), gas density, gas
temperature
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High-z Galaxies Requirements

• Large field of view
• Zgt10 galaxies very rare. Combine with lower z
  obs.
• ELT spectroscopy faster than JWST (per source)
  but needs multiplex for efficiency
• Image sizes 0.1-0.2
• Z gt10 probably integrated properties only
• 5 lt z lt 10 could be observed with 0.01 0.02
  pixels
• R 300-10000
• Z gt10 redshifts only
• 5 lt z lt10 higher resolution for stellar masses
  etc
• Wavelength range 1-2.4mm
• Up to z13 can be done in H band. Higher zs are
  harder!

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Re-ionisation history of the Universe

• Probe IGM and its reionisation structure to very
  high redshift
• Possible point sources at zgt10
• QSOs
• GRBs
• SNe (Pop III?)
• Requirements
• High R 1000 10,000
• Single sources
• Near-IR (JHK)
• gt 30m needed for R104 in NIR for all except
  brightest GRBs

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Cosmology and Fundamental parameters

• What drives the expansion of the Universe?
• What is the Dark Energy?
• Primary distance indicators e.g. Cepheids to
  z0.1
• Type Ia Supernovae to z4
• Type II SNe to z10 (and get SF history for
  free!)
• Gamma-Ray Bursts as distance indicators
• QSO absorption lines
• Direct measurement of expansion e.g. CODEX,
  R400,000
• Variation of fundamental parameters?

Keck observations of Q1422231 (Sargent Rauch)
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European ELT Design Study

• 01000 Project coordination
• 02000 Science requirements
• 04000 Wave-front Control
• 05000 Optical Fabrication
• 06000 Mechanics
• 08000 Enclosure infrastructure
• 09000 Adaptive Optics
• 10000 Observatory science ops
• 11000 Instrumentation
• 12000 Site Characterization
• 13000 System layout, analysis integrated
  modelling

• Started March 2005
• Collaboration of 30 participants
• Awarded Funding under EC Framework Programme 6
• Funding from ESO other participants
• Programme managed by ESO
• Runs for 4 yrs (2005-2008)
• Focus Enabling technology

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ELT Design Study

• Adaptive Optics
• Simulations of AO, MCAO
• APE
• large deformable mirrors
• Effects of wind
• Wind tunnel tests
• Sensors on Jodrell Bank
• Is an enclosure necessary?
• Instrumentation
• Flexure gravity stable platforms?
• ADC

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ELT Projects and Timescales

• European ELT
• ESO council pursuing an ELT is an urgent
  priority
• European Design Study started
• Design decision around 2008
• OWL (60-100m), Euro-50
• First light date depends on funding 2016/17
  (part-filled) to 2020/2021
• AURA MOU with ESO to collaborate in some areas

• GMT - Giant Magellan Telescope
• First mirror being made
• TMT - Thirty Meter Telescope
• Design study part funded
• Project office set up
• Design decision 2007
• Aiming for First light 2014/2015
• Japan, China, Australia also interested in ELT
  projects

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httpwww.saao.ac.za/IAUS232/
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Conclusions

• A lot of activity Worldwide
• Full science case recently completed
• European Technical Design Study has started
• Developing Science Requirements

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OWL simulation ESO
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THE END
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Comparison of 20-100m ELTs
Science Case 20m 30m 60m 100m
Solar System Y Y Y Y
Exo-Planets (direct detection) Gas Giants Y Y Y Y
Exo-Earths N N Y? Y
Proto-Planetary disks Y Y Y Y
Resolved Stellar Population Local Group N? Y Y Y
Virgo N N N Y
Massive Black Holes Y Y Y Y
Star formation History of the Universe Y Y Y Y
Physics of Galaxies and Dark Matter, z1-5 Y Y Y Y
Dark Energy Y Y Y Y
High-z Universe Sources of re-ionisation ? ? Y Y
R104 at zgt10 N N Y Y
The Unexpected Y Y Y Y

Assuming a standard site (e.g. Mauna Kea, rather
than Antarctica Dome C)
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Comparison with JWST

• JWST above atmosphere but many times smaller
• ELTs outperform JWST in many regimes
• High-res spectroscopy to 4mm (25mm for a 100m
  ELT)
• Imaging mode to 2.5mm (3.5mm)
• High spatial resolution
• Low-res spectroscopy 100m is more sensitive up
  to J band for resolved objects

unresolved
resolved
From GMT science case Detectable star formation
rates from Ly a emission-line spectroscopy with
an AO-fed near-IR spectrometer on the 20m GMT and
NIRSPEC on JWST (10 hour integrations). For this
case, a 20m telescope is able to reach about a
factor 4 fainter than JWST
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Exo-earth Detection Comparison (Angel, 2003)

• Telescope wave (mm) mode S/N (earth_at_10pc,
  t24h) space interf 4x2m 11 nulling 8.4 Darwin,
  TPF
• space filled 7m 0.8 coron 5.5-34 JWSTAntarct
  ic 21m 11 nulling 0.52 GMT 0.8 coron 5.9
  ground 30m 11 nulling 0.34 Celt, GSMT
                         0.8    coron 4.1
  ground        100m 11 coron 4.0 OWL
                         0.8 coron 46
  Antarctic 100m 11 coron 17 BOWLbetter OWL
                         0.8    coron 90

S/N is for detection of an Earth twin at
10pc t24hrs, QE0.2, bandwidth Dl/l0.2
100m has twice the REACH of TPF Surveys 1000
stars cf 100
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Context for 2010-2020

• Maturity of current generation telescopes
• AO ? ?/D performance, 2nd gen instruments
• Interferometry
• IR Faint object regime (K20), astrometry
  (?as)
• ALMA mm, sub-mm equivalent of optical
  facilities
• New space telescopes
• JWST, XEUS, TPF/Darwin precursors
• To obtain spectra of the faintest sources from
  HST need 30m
• To obtain spectra of the faintest sources from
  JWST need 100m

JWST
Gemini
VLT
Subaru Keck
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JWST comparison for first light

• Comparison with JWST
• JWST smaller but above atmosphere
• 100m better imager than JWST for l lt 2.5 mm
• Low-R 100m is more sensitive up to J band for
  resolved objects
• high R (gt1000), 30 or 100m can beat JWST
  depending on instrumentation.
• E.g. R 5000 100m beats JWST for l lt 5 mm

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Simultaneous Differential Imaging

• _at_ Specific wavelengths
• Cancel the speckles in real time
• ?Very high contrast (50k)
• Today on NaCo, VLT UT4
• Hartung, Close, Lenzen et al, AA July 2004

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Planet Detection from the GroundLardiere et al
2003

• Assumes
• System at 10pc
• S/N 3 in 10hrs in the J-band.
• Mauna Kea site

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Supernovae with an ELT
Type Ia PEAK
WM WL 0.0 0.0 0.3 0.7 1.0 0.0

• Imaging to z gt 5 AT PEAK
• Spectroscopy to z 4

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Point Sources at zgt10 Detection limits estimated
by J. Bergeron M. Bremer

• GRBs at R104
• 30m could do very bright GRBs and/or within 1
  day
• Bulk of GRB population at 10d need 100m
  (KAB27.4)
• Population-III SNe at R104
• Massive stars (140-260 M) should explode as very
  bright supernovae e.g. K25.2 at z12
  (extrapolated from Heger et al 2001)
• Detectable from the ground out to z16 for one
  month
• For zgt10 this needs ELTs of 70-100m size
• High-z QSOs
• Bright QSOs are rare. More typical QSOs cannot be
  observed at R104 even with 100m
• R2x103 could be done e.g. to explore the
  metal-enrichment of the IGM at early times from
  CIV forest.

GRB NASA / SkyWorks Digital

Need R104 NIR spectrograph
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Detectability of z8-20 galaxies

• Imaging
• Expect rest-frame UV at 8 ltzlt14 28-29
  mag (vega)
• Redshifted to J-K
• Feasible with 100m and AO
• Feasible at lower z (e.g. in J band) with 30m
• Are they resolved?
• half-light radii 0.2 at z6
• Are they knotty/more compact at higher z?
• Instrumentation should match the scale of objects

• Spectroscopy
• Ly-a in near IR from z 8 to 19
• EW 100-200A expected
• Detectable with 100m
• Asymmetry a challenge
• Require 5-10 arcmin field for multiplex
• Could be used as background to study IGM on 1
  arcmin scales (but resolved)

Hubble UDF image
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ELT Projects N. America
CELT
GSMT
Giant Magellan Telescope GMT (21m)
TMT Thirty Meter Telescope
VLOT
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ELT performance - Spatial Resolution
0.5 arcsec
Starburst region
WM WL 0.3 0.7 0.0 0.0
Giant HII region
0.6 arcsec
Compact HII region
VLT
Globular cluster
dramatic improvement in point-source sensitivity