LHC conference - Isfahan • Thermal History of the Universe and the standard Big-Bang model • The CMB • its origin • a tool for Cosmology • past and forthcoming observations CMB in the Planck area? (Planck is going to be launch May 6) Yannick Giraud-Héraud (APC – Paris)
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What can we learn from CMB in the Planck area? (Planck is going to be launch May 6)
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 . - PowerPoint PPT Presentation
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LHC conference - Isfahan
• Thermal History of the Universe and the standard Big-Bang model• The CMB• its origin• a tool for Cosmology• past and forthcoming observations
What can we learn from CMBin the Planck area?
(Planck is going to be launch May 6) Yannick Giraud-Héraud (APC – Paris)
Spherical Harmonics Expansion(equivalent to Fourier transform)
l 1/q : l=200 q=1 deg.
Thermal History of the Universe and the CMB7. Shape of the Power Spectrum (2/3)
LHC conference - Isfahan
Thermal History of the Universe and the CMB7. 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
8. CMB polarisation anisotropiesLinear polarisation is due to Thomson
scattering (Rees, 1968).
The polarisation of the CMB should be small as it is
Produced by temperature anisotropies
Thermal History of the Universe and the CMB
LHC conference - Isfahan
• 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 BWayne Hu
Thermal History of the Universe and the CMB8. CMB polarisation: decomposition in 2 modes E and B
LHC conference - Isfahan
( )17.0=τ
1.0=r
41055.6 −×=r
GeVEI16102~ ×
GeVEI15107.5~ ×
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r ≡ T 2
S2 ∝E I
M pl
⎛
⎝ ⎜ ⎜
⎞
⎠ ⎟ ⎟
4
- probe of the structure of the Universe- primordial gravitational waves: smoking gun probe of inflation
Thermal History of the Universe and the CMB8. CMB polarisation: power spectra
LHC conference - Isfahan
Key dates of the CMB observations
LHC conference - Isfahan
1) discovered at 7.35 cm (4 GHz) (Penzias & Wilson, 1964)
€
T = 2.725 ± 0.002K
highly uniform
510−≈ΔTT
2) dipole ΔT= 3 mK(Smoot et al. 1976)
skmv /600≈(Mather et al. 1999 - COBE)
CMB detection history
3) Perfect black body (COBE Mather et al., 1999) 4) Anisotropies at 7o
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
Plancklaunch scheduled May 6
Herschel
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
Low Frequency Instrument (LFI) Frequencies: 30 - 70 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) Sensitivity @30 GHz: ~5.4 mK; @70
GHz: 12.7 mK PI: N. Mandolesi (CNR –
Bologna/Italy) IS: M. Bersanelli (U. Milano/Italy)
This will allow to subtract foregrounds to the CMB
• Polarization measurement
LHC conference - Isfahan
High Angular Resolution (5’ for Planck and 7o for COBE)
LHC conference - Isfahan
High precision temperature measurement
COBE Planck
PlanckWMAP (8 ans)
~ 20 x WMAP sensitivity
Planck will have:
~ 3 x angular resolution
LHC conference - Isfahan
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 : 10000 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
Planck simulated maps
LHC conference - Isfahan
Temperature Power Spectrum
l l
• Power spectrum measurement up the 8th acoustic peak
• Just cosmic variance limited up to l ~2500
LHC conference - Isfahan
Polarisation Power Spectra
Cross-spectrum TE (t=0.17)
LHC conference - Isfahan
EE spectrum (t=0.17)Adding EE power spectrum to TT power spectrum will help to reduce the degeneracy to determine the cosmological parameters
Polarisation Power Spectra
LHC conference - Isfahan
Cosmological Parameters
Planck
WMAP
• 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
PLANCK
LHC conference - Isfahan
Dark Energy Equation of State
Dark energy, responsable of the acceleration of the expansion of the Universe, has an equation of state: p = w r
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
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 t = 0,091+-0.008
• Planck will be able to discrimate between different models of the first object formation
LHC conference - Isfahan
WMAP/Planck capacity measurement of ns
ns = 1 for the red solid line
LHC conference - Isfahan
WMAP/Planck capacity measurement of ns
ns = 0.95 and no running for the red solid line
LHC conference - Isfahan
Constraints on tensor modes with Planck
B polarization measurements at low l will put constraints on r
r=0.05 could be detected by Planck and upper limit r<0.03 (95% CL) could be set
• 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
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
LHC conference - Isfahan
And a lot of other studies will be performed by astrophysicists …
Clusters of galaxies: 30 000 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