Transcript Document 7304678

THE STANDARD MODEL OF
COSMOLOGY:
PAST, PRESENT AND FUTURE
Joe Silk
University of
Oxford
(visiting APC, IAP)
XLIth Rencontres de Moriond, La
Thuile
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?
A BRIEF HISTORY OF
COSMOLOGY
FRIEDMANN(1923) AND LEMAITRE (1927)
PROPOSED THE EXPANDING UNIVERSE
WHERE DARK
ENERGY
ORIGINATED
WHERE DARK
MATTER
A BRIEF HISTORY OF
COSMOLOGY, CTD
HUBBLE’S (1929) LAW
brightest
cluster
galaxies
A BRIEF HISTORY OF COSMOLOGY, CTD
RELIC RADIATION DISCOVERED
BY PENZIAS AND WILSON (1964)
These are 400 sigma error bars!
COBE 1990
FROM EXPANSION TO
INFLATION (1980)
Andrei Linde
“The Big Bang? Believe me, it was
very, very, very, very, very, very big”
Alan Guth
THE ONSET OF INFLATION AT
10-35 sec
THE INFLATIONARY UNIVERSE
COSMOLOGICAL
CONSTANT OR DARK
ENERGY?
In general, p=wwith w=-1 for the cosmological constant 
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!
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 197
THE MILKY
WAY
distance from centre of galaxy
rotation
velocity
Sofue and Rubin
N-BARYONIC DARK MATTER DOMINATES!
THE BARYON DENSITY IS KNOWN
…..AND VERY SUBDOMINANT
LIGHT ELEMENT
NUCLEOSYNTHESIS
IN THE BIG BANG
HELIUM
OmegaB measures the density of baryons
DEUTERIUM
LITHIUM
PRIMORDIAL SOUND WAVES
THE PHOTON-BARYON PLASMA
NON-BARYONIC WEAKLY INTERACTING DA
MATTER BOOSTS FLUCTUATION GROWTH
density
fluctuation
strength
time
FROM COBE TO
WMAP
1992
2006
TEMPERATURE VARIATIONS IN
THEbySKY
W + W =1 is measured
cosmic microwave

m
background peak: SPACE IS APPROXIMATELY
THEORY
EUCLIDEAN!
DATA as of
March 2006
BECAUSE OF PARAMETER DEGENERACIES
WE NEED TO DO BETTER THAN CMB ALONE
BARYON
OSCILLATIONS
THE DARK SIDE OF GALAXY FORMATION
MPA Millennium
simulation 2005
SUCCESS OF
LARGE-SCALE
STRUCTURE
dark matter
luminous matter
MILLENNIUM SIMULATION
WHERE IS THE HALO
SUBSTRUCTURE?
Diemand and Madau 2006
and the dark matter concentration?
THE MILKY WAY HALO: DWARF
GALAXIES
orbital
velocity
DWARF GALAXY ROTATION
CURVE
vp >13 km/s
distance from centre of galaxy
J. Taylor 2005
RESURRECTION OF DARK MATTER VIA NEW
PHYSICS ?
OR RESURRECTION VIA MESSY
ASTROPHYSICS ?
THE EFFECTS OF SUPERNOVA-DRIVEN WINDS
vp > 43 km/s
orbital
velocity
J. Taylor 2005
distance from centre of galaxy in kpc
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 kT~m/20 IMPLIES
RELIC DENSITY ~ weak/annihilation
PENDING SUCCESS OF DIRECT DETECTION ATTEMPTS,
THE MILKY WAY HALO PROVIDES
A LABORATORY FOR INDIRECT SEARCHES
VIA ANNIHILATIONS INTO
HIGH ENERGY PHOTONS, POSITRONS, NEUTRINOS,
ANTIPROTONS
COSMIC RAY POSITRON SPECTRUM
Baltz and Edsjo
PAMELA launch in 2006
positron energy (GeV)
FLUX
FROM GALACTIC
CENTRE
photon energy (GeV)
PREDICTIONS
Nezri et al. 2004
GLAST
2007
PROBING DARK ENERGY WITH
SUPERNOVAE
a nearby
a high redshift SN SN
observed wavelength
I.Hook et al 2005
W- Wm is
measured by
SN1a
acceleration inferred,
hence Wor dark energy
since +3p<0
magnitude
W
SN are
fainter
at high z
redshif
t
Wm
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
THE FUTURE FOR DARK ENERGY
• Dark Energy Survey (2009+)
• Pan-STARRS (2006-2009+)
US Air Force, 4 1.8m telescopes
3,000 sq deg in 5 bands
darkCAM
4-5 bands in visible band (4m)
10,000 sq deg to z > 1
4 days of war in Iraq
• The ultimate surveys
– LSST: 20,000 sq deg to z ~ 3 (2015)
>– 1SKA:
billion20,000
euros worth
of +
proposals
2015
sq deg
redshiftsuntil
(2020)
ULTIMATE AIM: MEASURE w TO A PERCENT
R. Trotta 2006
25,000 postdoc-years
GWFMOS
AAOmega, 1,000 sq deg (4m) (2006/9)
GWFMOS/HyperSuprime: z ~ 1-3 (8m)
(2013)
DES
• Spectrographs
10 years of expenditures
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