THE STANDARD MODEL OF COSMOLOGY: PAST, PRESENT AND FUTURE

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THE STANDARD MODEL OF COSMOLOGY PAST, PRESENT
AND FUTURE

• Joe Silk
• University of Oxford
• (visiting APC, IAP)

XLIth Rencontres de Moriond, La Thuile
March 22, 2006
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WE HAVE ENTERED A NEW ERA OF PRECISION COSMOLOGY
THAT HAS LEFT US WITH SOME OF THE GREATEST
PUZZLES IN PHYSICS
WHAT IS THE DARK ENERGY ?
WHAT IS THE DARK
MATTER?
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• A BRIEF HISTORY OF COSMOLOGY

FRIEDMANN(1923) AND LEMAITRE (1927) PROPOSED THE
EXPANDING UNIVERSE
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WHERE DARK ENERGY ORIGINATED

• WHERE DARK MATTER ORIGINATED

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A BRIEF HISTORY OF COSMOLOGY, CTD

• HUBBLES (1929) LAW

brightest cluster galaxies
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• A BRIEF HISTORY OF COSMOLOGY, CTD

RELIC RADIATION DISCOVERED BY PENZIAS AND WILSON
(1964)
These are 400 sigma error bars! COBE 1990
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FROM EXPANSION TO INFLATION (1980)
Alan Guth
Andrei Linde
The Big Bang? Believe me, it was very, very,
very, very, very, very big
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THE ONSET OF INFLATION AT 10-35 sec
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THE INFLATIONARY UNIVERSE
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COSMOLOGICAL CONSTANT OR DARK ENERGY?
In general, pw??with w-1 for the cosmological
constant ?
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A SPACE-TIME DIAGRAM OF THE UNIVERSE
FIRST LIGHT
THE DARK AGES

• ON ANGULAR SCALES ABOVE A DEGREE, WE ARE
• VIEWING QUANTUM FLUCTUATIONS IN THE SKY!

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SOME MORE PREHISTORY
ACOUSTIC RADIATION OSCILLATIONS

• BARYON ACOUSTIC OSCILLATIONS

Silk 1967
Peebles and Yu 1970
Sunyaev and Zeldovich 1970
Silk and Wilson 1981
Doroshkevich, Zeldovich and Sunyaev 1977
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THE MILKY WAY
distance from centre of galaxy
rotation velocity
Sofue and Rubin
NON-BARYONIC DARK MATTER DOMINATES!
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THE BARYON DENSITY IS KNOWN..AND VERY
SUBDOMINANT
HELIUM
LIGHT ELEMENTNUCLEOSYNTHESIS IN THE BIG BANG
OmegaB measures the density of baryons
DEUTERIUM
LITHIUM
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PRIMORDIAL SOUND WAVES IN THE PHOTON-BARYON
PLASMA
NON-BARYONIC WEAKLY INTERACTING DARK MATTER
BOOSTS FLUCTUATION GROWTH
density fluctuation strength
time
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FROM COBE TO WMAP
1992
2006
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TEMPERATURE VARIATIONS IN THE SKY

WL Wm 1 is measured by cosmic microwave
background peak SPACE IS APPROXIMATELY
EUCLIDEAN!
THEORY
DATA as of March 2006
BECAUSE OF PARAMETER DEGENERACIES WE NEED TO DO
BETTER THAN CMB ALONE
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BARYON OSCILLATIONS
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SUCCESS OF LARGE-SCALE STRUCTURE
THE DARK SIDE OF GALAXY FORMATION
MPA Millennium simulation 2005
dark matter
luminous matter
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MILLENNIUM SIMULATION
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WHERE IS THE HALO SUBSTRUCTURE?
Diemand and Madau 2006
and the dark matter concentration?
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THE MILKY WAY HALO DWARF GALAXIES

• DWARF GALAXY ROTATION CURVE

orbital velocity
vp gt13 km/s
distance from centre of galaxy
J. Taylor 2005
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RESURRECTION OF DARK MATTER VIA NEW PHYSICS ?

• OR RESURRECTION VIA MESSY ASTROPHYSICS ?

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THE EFFECTS OF SUPERNOVA-DRIVEN WINDS
vp gt 43 km/s
orbital velocity
J. Taylor 2005
distance from centre of galaxy in kpc
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SHEDDING LIGHT ON COLD DARK MATTER
MOTIVATED CANDIDATE LIGHTEST SUPERSYMMETRIC
PARTICLE IS EXPECTED TO BE IN MASS RANGE 100-1000
GeV
THERMAL FREEZE-OUT AT kTm?/20 IMPLIES RELIC
DENSITY ?weak/?annihilation
PENDING SUCCESS OF DIRECT DETECTION ATTEMPTS,
THE MILKY WAY HALO PROVIDES A LABORATORY FOR
INDIRECT SEARCHES VIA ANNIHILATIONS INTOHIGH
ENERGY PHOTONS, POSITRONS, NEUTRINOS, ANTIPROTONS
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COSMIC RAY POSITRON SPECTRUM
Baltz and Edsjo
PAMELA launch in 2006
positron energy (GeV)
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EGRET GAMMA RAY FLUXFROM GALACTIC CENTRE
photon energy (GeV)
PREDICTIONS
Nezri et al. 2004
GLAST 2007
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PROBING DARK ENERGY WITH SUPERNOVAE

• a nearby SN

a high redshift SN
flux
observed wavelength
I.Hook et al 2005
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WL - Wm is measured by SN1a
acceleration inferred, hence WL or dark
energy since r3plt0
magnitude
WL
SN are fainter at high z

• redshift

Wm
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Investigating dark energy

• The equation of state parameter w(z) p/?
• w -1
• w const ? -1
• w(z)
• Theoretical explanations are guided by
  observations

Spergel et al 2006
Seljak et al 2005
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THE FUTURE FOR DARK ENERGY

• Dark Energy Survey (2009)
• 4-5 bands in visible band (4m)
• 10,000 sq deg to z gt 1
• Pan-STARRS (2006-2009)
• US Air Force, 4 1.8m telescopes
• 3,000 sq deg in 5 bands
• Spectrographs
• AAOmega, 1,000 sq deg (4m) (2006/9)
• GWFMOS/HyperSuprime z 1-3 (8m) (2013)
• The ultimate surveys
• LSST 20,000 sq deg to z 3 (2015)
• SKA 20,000 sq deg redshifts (2020)

darkCAM
DES
GWFMOS
gt 1 billion euros worth of proposals until 2015
ULTIMATE AIM MEASURE w TO A PERCENT
R. Trotta 2006
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A NEW ERA OF PRECISION COSMOLOGY
FUNDAMENTAL ISSUES FOR PARTICLE ASTROPHYSICS
WHAT IS THE NON-BARYONIC DARK
MATTER? WHY IS THE DARK ENERGY SO
SMALL TODAY? WHY DOES IT DOMINATE
THE UNIVERSE SO RECENTLY? IS THE
UNIVERSE FINITE OR INFINITE? (W1/-e)
DID INFLATION OCCUR? HOW DID
GALAXIES FORM? ??????????????????

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