1. LHC conference - Isfahan
What can we learn from CMB in the Planck area? (Planck is going to be launch May 6)
Yannick Giraud-Héraud (APC – Paris)
Thermal History of the Universe
and the standard Big-Bang model
The CMB
its origin
a tool for Cosmology
past and forthcoming observations
LHC conference - Isfahan

2. LHC conference - Isfahan
The Big Bang Model
General Relativity (Einstein 1915 ; Friedmann 1922 ; Lemaître 1927)
matter
dark energy
curvature
Expansion
CMB
BBN
LHC conference - Isfahan
April 21, 2009

3. Thermal History of the Universe and the CMB
1. inflation (1/2)
GUT?
Brief period of exponential expansion
(factor 1026 in ~ s)
1) Resolve flatness, horizon, relic …
problems
2) Perturbation generation
density (scalar)
dm ~ EI6/V’ ~ 10-5
gravitational (tensor)
dog ~ (EI/MPlanck)4
LHC conference - Isfahan

4. Thermal History of the Universe and the CMB
1. inflation (2/2)
Slow roll potential, in favour today, are caracterized by 2 parameters
They are related to spectral index of the density fluctuations
V1/4~3.3x1016r1/4 GeV
LHC conference - Isfahan

5. Thermal History of the Universe and the CMB
2. nucleosynthethis
3. thermalization
LHC conference - Isfahan

6. Thermal History of the Universe and the CMB
4. temperature anisotropies
theory
2dF
LHC conference - Isfahan
Large-scale structure

7. Thermal History of the Universe and the CMB
5. Energy Contents of the Universe
What the Universe is made of?
For each component the density is defined in terms of the critical density:
Wcomposante = rcomposante/ rcritical
rcritical ~ 5. GeV/m3
LHC conference - Isfahan

8. Thermal History of the Universe and the CMB
6. Geometry of the Universe
Size of the horizon
at tdec
~100 Mpc
flat
closed
open
LHC conference - Isfahan
closed
flat
open

9. Thermal History of the Universe and the CMB
7. Shape of the Power Spectrum
(1/3)
Primordial Universe is dominated by radiation  no matter collapse
Baryon starts to collapse at matter-radiation equality
Acoustic waves induced by radiation pressure propagate at the speed of sound
Oscillations are frozen at the moment of decoupling
LHC conference - Isfahan

10. Thermal History of the Universe and the CMB
Spherical Harmonics Expansion
(equivalent to Fourier transform)
l  1/q : l=200  q=1 deg.
7. Shape of the Power Spectrum
(2/3)
= 0,9 ; m = 0,15
= 1 ; m = 0,25
= 1,1 ; m = 0,35
Statistically isotropic sky
l(l+1)/(2TCMB2)Cl
Angular power spectrum l
LHC conference - Isfahan

11. Thermal History of the Universe and the CMB
7. Shape of the Power Spectrum (3/3)
maps
power spectrum
Angular power spectrum
~number of fluctuations in respect to their size Cℓ
ℓ is inversely proportional to the angular size
ℓ=200 corresponds to q~1o
LHC conference - Isfahan

12. Thermal History of the Universe and the CMB
8. CMB polarisation anisotropies
Linear polarisation is due to Thomson scattering (Rees, 1968).
The polarisation of the CMB
should be small as it is
Produced by temperature
anisotropies
LHC conference - Isfahan

13. Thermal History of the Universe and the CMB
8. CMB polarisation: decomposition in 2 modes E and B
E modes – even parity :
B modes – odd parity :
- E modes are produced by quadrupolar sources
(density fluctuations and gravitational waves)
B modes are produced by gravitational waves and lensing of E modes
pure E
pure B
Wayne Hu
LHC conference - Isfahan

14. Thermal History of the Universe and the CMB
8. CMB polarisation: power spectra
- probe of the structure of the Universe
- primordial gravitational waves: smoking gun probe of inflation
LHC conference - Isfahan

15. Key dates of the CMB observations
LHC conference - Isfahan

16. LHC conference - Isfahan
CMB detection history
highly uniform
discovered at 7.35 cm (4 GHz)
(Penzias & Wilson, 1964)
2) dipole DT= 3 mK
(Smoot et al. 1976)
(Mather et al COBE)
3) Perfect black body
(COBE Mather et al., 1999)
4) Anisotropies at 7o
(COBE Smoot et al. 1992)
LHC conference - Isfahan

17. LHC conference - Isfahan
CMB detection history
Balloon experiments ( ): Boomerang, Maxima, Archeops
primary
secondary
pivot
horns
bolometers
cryostat
Archeops (2002)
from COBE scale to first acoustic peak
LHC conference - Isfahan

18. CMB detection history WMAP – NASA satellite (launch 2001)
2 back to back telescopes
Radiometers cooled down at 90 K
Bands at 23, 33, 41, 61 et 94 GHz
Angular resolution 13-52’
Sensitive to polarisation
Rotation 7.57 mHz
LHC conference - Isfahan

19. WMAP/ACBAR power spectrum
Cosmological parameters estimation
(WMAP+Acbar+CBI+Large Scale Structure Observations)
ns =
R<0.2
t =
LHC conference - Isfahan

20. Planck: an ESA satellite
CMB anisotropies measurements
(temperature and polarization)
International collaboration: European Community (Germany, Denmark, Spain,
Finland, France, Italy, Irland, Netherland, UK, Sweden), Canada, Norvege,
Switzerland, USA
LHC conference - Isfahan

21. LHC conference - Isfahan
Planck
launch scheduled May 6
Herschel
LHC conference - Isfahan

22. LHC conference - Isfahan
Planck is going to orbit around the 2nd Lagrangian point of the Sun-Earth-Moon system
the sky will be scanned in 6 months
the mission is expected to last 30 months
LHC conference - Isfahan

23. Low Frequency Instrument (LFI)
Frequencies: GHz
Wavelengths: 1cm - 5 mm
radio detectors (22)
Temperature: 20 K (Front-end), 300 K (Back-end)
Angular resolution: 12' (70 GHz) à 33' (30 GHz)
GHz: ~5.4 GHz: 12.7 mK
PI: N. Mandolesi (CNR – Bologna/Italy)
IS: M. Bersanelli (U. Milano/Italy)
LHC conference - Isfahan

24. High Frequency Instrument (HFI)
Frequencies: GHz
Wavelenghts: 3mm à 400µm
Detectors: 52 bolometers
Temperature: 0.1 K
Angular resolution: 5' (850 GHz) à 9.2' (100 GHz)
GHz: ~ 5mK
PI: J.L. Puget (IAS - Orsay)
IS: J.M. Lamarre (LERMA – Paris)
LHC conference - Isfahan

25. Thermal Architecture of Planck HFI
Bolomètres 4K
1.6K
18K
0.1K
LHC conference - Isfahan

26. LHC conference - Isfahan
Bolometers “Spider web”(Caltech/JPL)
121 Bolometers on a Wafer
NTD Germanium
857 GHz Bolometer
LHC conference - Isfahan

27. Frequency Observations
Large bandwith coverage : 9 bands
This will allow to subtract foregrounds to the CMB
Polarization measurement
LHC conference - Isfahan

28. High Angular Resolution
(5’ for Planck and 7o for COBE)
LHC conference - Isfahan

29. High precision temperature measurement
COBE
Planck
WMAP (8 ans)
Planck
Planck will have:
~ 20 x WMAP sensitivity
~ 3 x angular resolution
LHC conference - Isfahan

30. Main Planck Scientific Goals
for temperature measurements : definitive measurements up to l=2000
only limited by photon noise of the CMB (astrophysical foregrounds
become the major source of uncertainty)
CMB polarization measurements will be the challenging part of Planck
for E mode up to l=1000
Impact on the knowledge of the Big Bang model and on
Fundamental Physics
cosmological parameters at the % level
first constraints on inflation
Study of the large scale structure will be adressed through :
Sunyaev-Zeldovitch survey : clusters as good tracers of the
dynamics of the Universe
B polarization measurement
study of the Milky Way
limit on neutrino mass
LHC conference - Isfahan

31. LHC conference - Isfahan
Planck simulated maps
LHC conference - Isfahan

32. Temperature Power Spectruml l
Power spectrum measurement up the 8th acoustic peak
Just cosmic variance limited up to l ~2500
LHC conference - Isfahan

33. Polarisation Power Spectra
Cross-spectrum TE (t=0.17)
LHC conference - Isfahan

34. Polarisation Power Spectra
EE spectrum (t=0.17)
Adding EE power spectrum to TT power spectrum will help to reduce
the degeneracy to determine the cosmological parameters
LHC conference - Isfahan

35. Cosmological Parameters
Improvment of the knowledge of the
cosmological parameters
Ex: Ωb précision
10 times better
than with WMAP.
Degeneracies will be reduced (polarisation)
Ex: discrimination between adiabatic
and isocurvature perturbations
WMAP
Planck
PLANCK
LHC conference - Isfahan

36. Dark Energy Equation of State
Dark energy, responsable of the acceleration of the expansion of the
Universe, has an equation of state:
p = w 
For a pure cosmological constant:
w = -1
Planck will contribute to the measurement of w together with other probes (SNIa, Large Scale Structure, Baryonic Acoustic Oscillation, weak lensing, …),
LHC conference - Isfahan

37. Reionisation of the Universe
After a period where the Universe was neutral, a phase of reionisation occured when the first objects (stars?) have been created
Signature at large angular scales: pic dans le spectre EE (WMAP)
WMAP+ACBAR+LSS Optical depth  = 0,
Planck will be able to discrimate between different models of the first object formation
LHC conference - Isfahan

38. WMAP/Planck capacity measurement of ns
ns = 1 for the red solid line
LHC conference - Isfahan

39. WMAP/Planck capacity measurement of ns
ns = 0.95 and no running for the red solid line
LHC conference - Isfahan

40. Constraints on tensor modes with Planck
B polarization measurements at low l will put constraints on r
(Planck 24 month survey)
Efstathiou, Gratton astroph:
simulation with r=0.1 and t=0,17
simulation with r=0.1 and t=0,17
r=0.05 could be detected by Planck
and upper limit r<0.03 (95% CL) could be set
LHC conference - Isfahan

41. Non-gaussianity properties of the anisotropies
Inflation models predict nearly perfect model dependant Gaussian fluctuations
Detection of non-gaussianity will be crucial to discriminate between these models
Methods: kurtosis, skewness, 3 point statistics, test of isotropy …
WMAP data
Very cold region
LHC conference - Isfahan

42. Secondary anisotropies: gravitational lensing of the CMB
During their trip, CMB photons are gravitationaly slightly deviated by
structures of the Universe
Coherent deviation of the polarisation at large scale: B mode polarisation at small scale (leak from E mode to B mode) Non-gaussian signatures should be detected by Planck
Neutrino mass affects structure formation Upper limit on mn: 0.15 eV
LHC conference - Isfahan

43. And a lot of other studies will be performed by astrophysicists …
Clusters of galaxies: clusters will be detected
by Planck using Sunyaev-Zel’dovitch effect
(interaction of CMB photons with hot electron gaz in
the core of the galaxy clusters)
Extragalactic sources (first survey since FIRAS 1992
with l>100mm)
Study of the Milky Way: dust, free-free,
synchrotron radiation  magnetic field
LHC conference - Isfahan