Two-part talk

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Two-part talk

• Observed properties of dark matter a progress
  update on dynamical studies of dwarf spheroidal
  galaxies
• The European Extremely Large Telescope (in
  brief..)

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Update on the EuropeanExtremely Large Telescope

• Gerry Gilmore
• Chair, Steering Committee
• Chair, OPTICON

ELT Design Study Contract No 011863A
technology development programme funded by the
European Community under its Framework Programme 6
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Science case overview

• Three priority themes

Exo planets Direct detection Indirect
detection Circumstellar disks
Galaxy Formation First galaxies Stellar
populations Physics of galaxies
Frontiers of Physics Cosmological parameters
Fundamental parameters Black Holes
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Radial velocity measurements of the nAnd system
Butler et al (1999)

• Direct imaging detection
• Indirect detection (radial velocity)
• lower mass planets e.g. earth-like planets
  around solar type stars
• Large collecting area (requires high spectral
  resolution)
• Stellar disks
• Detection of gaps where planets are forming
• requires high dynamic range (103-105)
• Spectroscopy to probe dynamics and chemistry
  (dust, gas ices, organic materials)

Simulations of formation of gas giant planets via
fragmentation of proto-planetary disks (Meyer et
al 2004)
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Resolved Stellar populations
Aparicio and Gallert (2004)

• Measuring age chemical composition of
  individual stars
• ? quantify star formation and assembly histories
  of a galaxy
• Map dark matter
• (i) Colour-magnitude diagram (photometry)
• A 40m can reach RGB stars for representative
  galaxies in Virgo/Fornax at 17Mpc
• (ii) Spectroscopic chemical abundances
  kinematics
• High resolution (diffraction-limited)
• Large collecting area

M87 in the Virgo cluster (Gendler)
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Galaxy Formation- The first galaxies

• Redshift 6-7 galaxies have been found
• Evidence for higher redshift galaxies
• Old stellar populations, SMBH already seen at z6
• Universe is ionised by something!
• Find earlier galaxies by imaging JWST? ELT
  imager?
• Need ELT for continuum spectroscopy (z and
  physical properties)
• Large collecting area (faint galaxies)
• Large Field of View

HST images of z5 galaxies (Bremer Lehnert
2005)

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Frontiers of Physics

• Dark Matter
• Probe via galaxy dynamics
• Dark Energy
• Type Ia SNe spectroscopy at hi-z
• Direct measurement of expansion
• e.g. CODEX, R150,000
• Variation of fundamental parameters
• Black Holes
• angular resolution of ELT probes sphere of
  influence

Artists concept of an AGN (GLAST/NASA)
Keck observations of Q1422231 (Sargent Rauch)
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E-ELT Current status

• Technical review of general design work late 2005
• Specific designs under study for next review late
  2006
• Apertures in range 30m-60m considered, 30-40m
  likely driven by schedule ? to match JWST and
  ALMA cost and technology
• Major science/technology meeting, 11/2006
  (Marseille)
• Then progress to detailed design
• Cost 1G/euro
• Schedule operation 2016 the second set of
  Great Observatories
• ESO Council resolution We will do it, and not be
  late
• Two similar projects, status and timetables in US
• Presentation of major 2015 projects, and funding
  agency overviews, next week _at_ Prague, IAU GA
  (Special Session 1)

Real why more photons and resolution more
science!
9
Some observed properties of Dark Mattera
progress report on a dynamical study of the
nearby dSphs

• Gerry Gilmore
• IoA Cambridge
• Mark Wilkinson, Jan Kleyna, Wyn Evans,
• Justin Read, Andreas Koch, Rosie Wyse, Mike
  Irwin, Eva Grebel,,.

Data from VLT, Keck, Gemini, AAT, WHT, INT,
eso2.2
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The early context

• The standard value for local DM at the Sun
  is 0.3GeV/cc, all in a halo component
• (cf pdg.lbl.gov Eidelman etal 2004)
• the original work, and origin of this value, is
  the first analysis to include a full 3-D
  gravitational potential, parametric modelling,
  and a direct determination of both the relevant
  density scale length and kinematic (pressure)
  gradients from data, allowing full DF modelling
  for the first time
• Kuijken Gilmore 1989 (MN 239 571, 605,
  651), 1991 (ApJ 367 L9) 1989 Gilmore, Wyse
  Kuijken (ARAA 27 555)
• Cf Bienayme etal 2006 AA 446 933 for a recent
  study
• Dark halos are predicted down to sub-earth
  masses but
• Neither the local disk, nor star clusters, have
  DM Given the absence of a 100pc local
  enhancement, what is the smallest scale on which
  DM is concentrated?

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New data UP TO 600 s/GAL
Leo I
Note very low outer-most dispersions in Sextans,
Draco, UMi not yet understood Expected
dispersion if no DM lt1km/s
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dSph modelling

• 1) Use Jeans eqn simple, and robust also
• 2) Multi-component DF models developed (see
  Wilkinson etal MN 330 778 2002 for details)
• Construct parameterised equilibrium dynamical
  models vary halo shape, and mass, stellar
  velocity anisotropy
• Predict line of sight kinematics convolve with
  observational effects (errors, binaries,
  sampling)
• Compare with individual data to find best-fit
  model
• OTHER COMPLEMENTARY WORK
• Deep HST studies to show stellar M/L normal,
  ie agrees with Kroupa, Tout, Gilmore local IMF
  -- Wyse etal 2002 New Astr 7 395 for UMi
• Galactic tides, feedback, etc modelled (eg Read
  etal 2006 MN 366 429)
• NOTE many earlier studies used scaled
  tidally-limited star-cluster (King-) models
  these are invalid for extended low-density
  systems.

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Breaking the degeneracy first steps
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Cold subsystems imply shallow density profiles
NOT as CDM prediction
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Can we break the anisotropy-mass degeneracy?
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Distribution Function Models
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Alternative gravity theories?
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Dark matter systematics the 2005 state of play
Only 8 galaxies, factor 40 in luminosity..
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Systematic properties of DM I--minimum mass,
scale, dispersion?2006 extend dynamic range by
2 mags

• Red line constant mass DM halo,
• M4x107M?
• apparent lower mass boundary
• Some data are old, central M/L only
• Now a factor of 200 in luminosity, 3000 in M/L

Figure from astroph-0602186
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Systematic properties of DM I--minimum mass,
length, dispersion?
Observed properties of UMa predicted
New Boo dwarf data under analysis ?
Relation now extends from 40X to 500X in L, from
3 to 3000 in M/L 5 new dSph discovered this
year, under study
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Exclusion?
?Globular star clusters, no DM?
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Systematic properties of DMcores, maximum
central density?
Survival of cold local structures in UMi
plausibly an evolved star cluster --
requires cored mass distribution
Consistent with cored halos
15GeV/cc?
LEAST LUMINOUS
? UMa
Jeans eqn mass profiles total masses 38x107
Msun Unreliable method at large radius better
models underway
?Fornax
? Leo I
MORE LUMINOUS
Central density ranking is the inverse rank
order to CDM prediction MOND fails
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New dSph and debris being discovered now
test predictions!
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Systematic properties of DM -IIcores, maximum
central density?
Jeans eqn mass profiles Total masses 38x107
Msun Unreliable method at large radius
Consistent with cored halos
15GeV/cc?
LEAST LUMINOUS
? UMa
Survival of cold local structures in UMi
plausibly an evolved star cluster --
requires cored mass distribution Kleyna etal
2003 UMi Kleyna etal 2004 Sext
?Fornax
? Leo I
MORE LUMINOUS
Central density ranking is the inverse rank
order to CDM prediction
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Distribution Functions
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Exo-planets

• How common are systems like ours?
• How do planetary systems form?
• To date many planets have been detected
  indirectly
• Direct detection
• Mass, radius, temperature, composition
• ELT will provide large samples of mature giant
  planets in reflected light
• Earth-like planets may be within reach
• Large collecting area (faint planets)
• Large diameter very high spatial resolution and
  contrast 109

Young Giant (5MJ) Exo-planet observed with
VLT/NACO (Chauvin et al 2004)
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Anisotropic Plummer Models
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dark matter on small scales

• A vast increase in precise stellar kinematic data
  allows more sophisticated derivation of mass
  profiles in the dSph- the smallest galaxies.
• UMa discovered 2005 and Boo (2006) extends
  to M/L 500-3000!! 4 more found last week
• All are consistent with
• Central mass cores, not cusps
• Central mass density 20GeV/cc
• Dispersion 6-9km/s
• Scale length few x100pc
• DM minimum mass? 5x107M?
• We have new dSph under study (today), to extend
  the sample further, and see if these numbers are
  really significant
• MOND fails

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The Local Groupdetailed test

• Locally, gt90 halo stars are old recent mergers?

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The Local Groupdetailed test

• small scales least clear,
• Are the predictions reliable?

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Non-Standard Models

• Draco vs MOND
• Mond M/L is still 19

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Are there other unmodelled effects
time-dependent dynamics?
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Umi direct HST star counts
Wyse etal, luminosity function for Umi is like
M92, M15 at low masses. High mass indirect limit
from chemical evolution.
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Orbit, Tidal radius

• Draco light is not tidally limited

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High-mass, high-redshift IMF

• Element ratio modelling limits IMF slope

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dSph Stellar IMF

• Deep direct star counts (Wyse etal)
• Element ratio limits at high mass
• Deep ISO photometry (GG Unavane)
• All imply an invariant IMF
• ? Stellar M/L2-4

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dSph satellite galaxies what, why?

• Lowest stellar mass galaxies known
• In CDM test regime eg famous sub-structure
  problem
• (ie, gt1000 predicted, 10 found)
• Have high M/L (Aaronson 1983) 3 stars in Draco
  to deduce M/L30 ? 1-D velocity dispersion
  high
• 1990 Pryor Kormendy showed that extended dark
  halos were consistent with available data
• 1997 Mateo first extended dispersion profile
  Fornax
• 1998 Mateo noted M/L vs L may imply min DM mass.
• 2006 extended dispersion profiles available for
  Draco, UMi, Leo I, Leo II, Fornax, Scl, Carina,
  1-D for UMa, AndII, AndIX with very many
  high-precision data up to gt500 stars/galaxy
  new ones to come complete sample
• Kleyna etal 2000,2002,2003,2004, 2005,
  2006Tolstoy etal 2004, 2006 Munoz etal 2005
  Walker etal 2005 Chapman etal 2005 Wilkinson
  etal 2004, 2006, Koch etal 06a, 06b