Science with the European ELT Isobel Hook, U' Oxford

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Science with the European ELTIsobel Hook, U.
Oxford
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European ELT Discovery Potential

• European ELT a 42m diameter, adaptive telescope
• Diffraction limited images 5x sharper than 8m or
  JWST
• Larger collecting area
• Enables new science, complements other facilities

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Spatial Resolution
1 arcsecond
E-ELT (diffraction limit a few milliarcsec in
the near-IR)
Seeing limited
8m AO
HST
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ELT science case development in Europe
Florence 2004
Marseilles 2003
Science case documents
Marseilles 2006
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Science Working Group Report, April
2006 http//www.eso.org/sci/facilities/eelt/
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ELT and the Astronet Science Vision

• A. Do we understand the extremes of the
  Universe?
• Measure the evolution of the dark-energy density
• Test for a consistent picture of dark matter and
  dark energy
• Understand the astrophysics of compact objects
  and their progenitors
• B. How do galaxies form and evolve?
• Map the growth of matter density fluctuations in
  the early Universe
• Detect the first stars, black holes, and galaxies
• Determine the evolution of the galaxy cluster
  mass function
• Make an inventory of the metal content of the
  Universe over cosmic time
• Measure the build up of gas, dust, stars, metals,
  magnetic fields, masses of galaxies
• C. What is the origin and evolution of stars and
  planets?
• Determine the initial physical conditions of star
  formation
• Unveil the mysteries of stellar structure and
  evolution, also probing stellar interiors
• Understand the life cycle of matter from the
  interstellar medium
• Determine the process of planet formation
• Explore the diversity of exo-planets in a wide
  mass range from giants to Earth-like

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Direct detection of a Super Earth

• How common are systems like ours?
• How do planetary systems form?
• Direct detection
• Mass, orbit, temperature, composition
• Requires ultra-high contrast 10-9
• Simulations of photon-limited case (idealised)
  show rocky planets detectable to 5-10pc
• Now studying systematic effects (e.g. speckles)

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Archaeological Record of Galaxy formation

• ELT can resolve individual stars in galaxies
  beyond our own Local Group
• Imaging in densely crowded fields in the Virgo
  cluster
• Spectroscopy to 5-10Mpc, Sculptor/Leo groups or
  further
• Kinematics, metallicities

1 arcsec
Simulation by J. Liske 10hr K-band LTAO
Two stars in Sculptor (3Mpc) with different
metallicities (Tolstoy et al 2001)
HST image of NGC 253 (Sculptor group)
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Watching Galaxies Form1 lt z lt 5

• Mergers or ordered rotation?
• Distinguish via velocity maps

z 4 (1.4bn yrs)
Massive, rotating disk galaxy 3 bn yrs after the
Big Bang, Observed with Adaptive Optics IFU
on VLT (Genzel et al 2006)
0.5 (4 kpc)
Simulation (M. Puech) typical rotating
disk 42-m ELT, 10-hr integration, MOAO

• Large, representative sample requires
  multiple-IFUs fed by AO (EAGLE)

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Watching the Universe accelerate in real time

• What is the Dark Energy?
• ELT can measure acceleration directly, in real
  time
• Fundamentally different probe (dynamical vs
  geometrical)
• Weak signal cm/s/yr. Requires
• ELT (collecting area)
• 20 year monitoring campaign
• Ultra-high stability, high-resolution
  spectrograph (CODEX)
• Variation of fundamental constants?

QSO absorption lines 2ltzlt4
See paper by J. Liske et al., MNRAS, in press
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Conclusions

• A very broad science case, e.g.
• First image of a Super Earth
• Watching galaxies form
• Real-time observations of the accelerating
  Universe
• Unique facility for many of the Astronet science
  vision questions
• Vast discovery potential for new science
• Note E-ELT science session at JENAM, September
  2008

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The End
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Comparison with JWST

• Angular resolution
• ELT 5x that of JWST
• Sensitivity
• For wavelengths l gt 2mm
• JWST best for imaging and R lt 3000 spectra
• ELT best for high-res imaging and high-R spectra
• For l lt 2mm
• JWST suitable for very deep imaging of extended
  sources
• ELT best for Rgt 100 spectroscopy
• Instrumentation, available time, mission
  lifetime

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Example EAGLE / HARMONI setup

• Multiple IFU observations of lensed high-z
  galaxies
• kinematics of lenses

z 4.88 lensed galaxy
HARMONI
EAGLE
Cluster at z0.78 Image Mark Swinbank
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Watching Galaxies Form (1)The First Galaxies
z 6.96 galaxy spectrum from Subaru (Iye et al
2006)

• What re-ionised the Universe?
• Highest confirmed redshift z7
• Higher-z candidates already known but too faint
  for spectroscopic confirmation
• JWST targets (or from ELT itself)
• ELT spectroscopy
• Measure z basic physical parameters
• Search for HeII lines (indicator of the first
  stars)

z10 galaxy candidate spectrum from
Keck/NIRSPEC (Stark et al)
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Planetary Birthplaces stellar disks

• How does matter accrete onto a forming star?
• How do planets form in the disk?
• What is the disk made of?
• Imaging
• Look for gaps and structure
• 40m has resolution of 1AU at 20pc at 10mm, 5 x
  JWST
• Spectroscopy
• dynamics
• composition - (e.g. silicates, water, organic
  materials)

Simulation of the formation of planets via
fragmentation of the disk (Armitage et al)
HARMONI and METIS
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Diffraction limits (milliarcsec)

• Combination with collecting area gives enormous
  gains
• t D-4 in some cases
• or 6.5 mag gain vs 8m in natural seeing

few mas in near IR few 10s mas in Mid-IR
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European ELT SWGProminent Science Cases

• Exo-planets
• Direct detection
• Radial velocity detection
• Initial Mass Function in stellar clusters
• Stellar disks
• Resolved Stellar Populations
• Colour magnitude diagrams
• Abundances and kinematics
• Detailed abundances
• Black Holes
• The physics of galaxies
• Metallicity of the low-density IGM
• The highest redshift galaxies
• Dynamical measurement of the Universal expansion

• Selected from larger set
• Not complete!
• www.eso.org