Transcript Extremely Large Telescopes

Extremely Large Telescopes
Isobel Hook
University of Oxford
JENAM 2005
OPTICON ELT Science Working Group
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OPTICON activity under EU FP5 & FP6
Over 100 volunteers
Open to all
Parallel to Design Study
Recent meeting: Florence, Nov 2004
JENAM 2005
ELT Projects - Europe
Euro-50
VLT –UT1
OverWhelmingly Large (OWL)
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
Our Solar System
Object
Surface
Resln*
(km)
~106 Illustrative
+ Repeat
observations
Pixels
across
typical disc
Moon
4m
Mars
~2
Asteroids
Notes
Equivalent to
flotilla of
spacecraft
3-7
3400
~200 Ceres, Vesta
Jupiter
8
~500 moons
Saturn
15
~300 Titan
Uranus
30
~25 Ariel
Neptune
45
~90 Triton
Pluto
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~90
Varuna
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~15 Large TNO
*Assuming 100m telescope diffraction limit at 1mm
Jovian Satellite Io
JENAM 2005
ELT terrestrial planet studies – are we
alone?
• 30m telescope can observe
mature gas-giant exoplanets to 10-20pc
Candidate Hot Giant Exo-planet
observed with VLT/NACO (Sep 04)
• To study exo-earths, need:
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large sample (~1000 stars)
to reach ~30pc
resolution (~33mas)
contrast ~1010
>50m
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Spectroscopy > O2, H2O
Orbits
Whole systems
GQ Lupi b – Neuhauser et al (Apr 05)
JENAM 2005
Planet detection models for OWL
O. Hainaut and R. Gilmozzi
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Simulated eX-AO-corrected psf
• Spectra of Sun, Jupiter, Earth
• Sky
• OWL efficiency simulator
• Photon noise
• cophasing errors
Filter R, t= 10ks
strehl=0.5
d = 10pc, D=100m
Jupiter: S/N=80
Earth: S/N=10
100m may detect Earth to 25pc
Spectroscopy to about 15pc
0.5”
JENAM 2005
Factors affecting contrast
• Now have quantitative estimates/ simulations - or
requirements on control for:
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JENAM 2005
Seeing speckles (differential imaging)
Scintillation
Piston errors (static & non-static)
Coronography
Wavelength difference between WFS and science
Non common-path WF errors
Planets and Stars
• Giant planets
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Moons
Rings
• Planetary disks
• gaps
• Low-mass (planetary?)
objects
• Jets, outflows
Simulation of planetary disk formation
– Lucio Mayer
Gemini observations of the Orion nebula
- Lucas, Roche & Riddick (2003)
HST image of Eta Carinae
-Morse & Davidson, NASA
Resolved Stellar populations and Galaxy
Formation
• Measuring age & chemical
composition of individual stars
> 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)
JENAM 2005
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
JENAM 2005
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!)
Artist’s conception of an AGN (GLAST/NASA)
JENAM 2005
M. Hughes et al
Evolution of galaxies:
Physics of galaxies 1<z<5
• Goal: to understand formation
of galaxies & feedback
processes (SNe, AGN)
• Want to spatially resolve on kpc
scales:
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Star formation history
Stellar mass
Extinction
Metallicity
Ionisation state
Line shapes (> winds)
Internal dynamics
• Relate this to galaxy haloes
JENAM 2005
Velocity fields of distant galaxies from
GIRAFFE Integral-field Unit observations
(Flores et al 2004)
Evolution of Galaxies:
Assembly of galaxy haloes
• Map evolution dark
matter from 1<z<5
• 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
JENAM 2005
Evolution of galaxies: Requirements
• Similar for galaxies &
haloes
• Multiple IFUs: 2 types
– 10 with 2”x2”
– 100 with 0.5”x0.5”
• R~ 5000-10000
• 0.5-2.5mm
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• AO system for resolved
studies (0.01-0.05”)
• FOV >2’ (10’ goal)
• ~ 1 night per field with a
100m
JENAM 2005
FALCON concept (Hammer et al)
The First Galaxies
• z~ 6-7 galaxies have been found
• Higher-z must exist
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Old populations seen at z~6
Z~6 QSOs imply massive galaxies
at earlier epochs
Universe is ionised by something!
• Find by imaging
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Use JWST to find candidates?
Probably too faint for JWST
continuum spectroscopy
• 60m could reach mH~29 in 100hrs
(depending on source size)
• Spectroscopy at z>10 hard even
for 100m
The Universe at z=6.1 (Gnedin 2000)
Neutral H, ionising intensity (z), gas density, gas temperature
Re-ionisation history of the Universe
• Probe IGM and its reionisation structure to
very high redshift
• Possible point sources at z>10
QSOs
GRBs
SNe (Pop III?)
• Requirements:
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JENAM 2005
High R: 1000 –10,000
Single sources
Near-IR (JHK)
> 30m needed for R=104 in NIR for all except
brightest GRBs
Cosmology and Fundamental parameters
• What drives the expansion of the Universe?
• What is the Dark Energy?
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JENAM 2005
Primary distance indicators – e.g. Cepheids to z~0.1
Type Ia Supernovae to z~4
Type II SNe to z~10 (and get SF history for free!)
Gamma-Ray Bursts as distance indicators
QSO absorption lines
• Direct measurement of expansion [e.g. CODEX, R~400,000]
• Variation of fundamental parameters?
Keck observations of Q1422+231 (Sargent & Rauch)
European ELT Design Study
• 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
JENAM 2005
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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
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
JENAM 2005
ELT Projects and Timescales
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
JENAM 2005
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
http:www.saao.ac.za/IAUS232/
JENAM 2005
Conclusions
A lot of activity Worldwide
Full science case recently completed
European Technical Design Study has started
Developing Science Requirements
JENAM 2005
OWL
simulation
ESO
THE END
JENAM 2005
Comparison with JWST
resolved
unresolved
• 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
JENAM 2005
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
Exo-earth Detection Comparison (Angel,
2003)
Telescope
wave (mm)
mode
S/N* (earth@10pc, t=24h)
space interf
space filled
4x2m
7m
11
0.8
nulling 8.4
coron
5.5-34
Darwin, TPF
JWST
Antarctic
21m
30m
ground
100m
Antarctic
100m
nulling
coron
nulling
coron
coron
coron
coron
coron
GMT
ground
11
0.8
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0.8
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0.8
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0.8
0.52
5.9
0.34
4.1
4.0
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90
Celt, GSMT
OWL
BOWL=better OWL
S/N is for detection of an Earth twin at 10pc 100m has ~twice the REACH of TPF
t=24hrs, QE=0.2, bandwidth Dl/l=0.2
Surveys ~1000 stars cf 100
Context for 2010-2020
• Maturity of current generation telescopes
– AO  l/D performance, 2nd gen instruments
• Interferometry
– IR: “Faint object” regime (K~20), astrometry (mas)
– 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
JENAM 2005VLT
Gemini
Subaru
Keck
JWST
Planet Detection from the Ground
Lardiere et al 2003
Assumes
•System at 10pc
•S/N =3 in 10hrs
in the J-band.
•Mauna Kea site
JENAM 2005
Point Sources at z>10
Detection limits estimated by
J. Bergeron & M. Bremer
• GRBs at R=104
– 30m could do very bright GRBs and/or within ~1 day
– Bulk of GRB population at +10d need 100m (KAB=27.4)
GRB NASA /
SkyWorks
Digital
• Population-III SNe at R=104
– Massive stars (140-260 M) should explode as very bright
supernovae: e.g. K=25.2 at z=12 (extrapolated from Heger et
al 2001)
– Detectable from the ground out to z~16 for ~one month
– For z>10 this needs ELTs of 70-100m size
• High-z QSOs
– Bright QSOs are rare. More typical QSOs cannot be observed at
R=104 even with 100m
– R=2x103 could be done: e.g. to explore the metal-enrichment
of the IGM at early times from CIV forest.
Need R=104 NIR spectrograph
JENAM 2005
Detectability of z=8-20 galaxies
Imaging
Spectroscopy
• Expect rest-frame UV at
• Ly-a in near IR from z = 8 to
8 <z<14 = 28-29 mag (vega)
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• Redshifted to J-K
• EW 100-200A expected
• Feasible with 100m and AO
– Detectable with 100m
• Feasible at lower z (e.g. in J
– Asymmetry a challenge
band) with 30m
• Require 5-10 arcmin field
for multiplex
• Are they resolved?
– half-light radii 0.2” at z~6
• Could be used as
– Are they “knotty”/more
background to study IGM on
compact at higher z?
1 arcmin scales (but
– Instrumentation should
resolved)
match the scale of objects
JENAM 2005
Hubble UDF image
ELT Projects – N. America
Giant Magellan
Telescope
GMT (21m)
CELT
GSMT
TMT: Thirty Meter Telescope
VLOT
JENAM 2005
ELT performance - Spatial Resolution
0.5
arcsec
Starburst region
0.6 arcsec
Giant HII region
Compact HII region
AO-8m
100m
VLT
ELT
Globular cluster
+ dramatic improvement in point-source sensitivity
JENAM 2005
WM WL
0.3 0.7
0.0 0.0