1. The Cosmic Microwave Background and the WMAP satellite results
Elena Pierpaoli (Caltech)
siamo tanto belli e bravi

2. Outline:
What is the Cosmic Microwave Background (CMB) radiation and why it is important
Properties: frequency spectrum, temperature, (an)isotropy
The satellite missions: COBE, WMAP and Planck
The sky map and the power spectrum
Where we stand now: the WMAP results
Perspectives: Planck predictions

3. Recombination
Reionization

4. Penzias and Wilson discovered the ~3 K CMB radiation in 1965
(and received the Nobel Prize for it in 1978)

5. The space experiments:

6. Properties: the frequency spectrum
The CMB radiation is a
black body with temperature
T=2.726

7. Properties: isotropy and anisotropies
The CMB radiation is isotropic
We are moving with respect to the CMB rest frame
There are tiny anisotropies, imprints of matter-radiation fluctuations.

8. The CMB anisotropies map

9. The power spectrum DT(q,f) = S al,m Yl,m (q,f) cl = Sm |al,m|2
The power spectrum is the most compact way to
describe (all) the cosmological information in a sky map. It allows efficient comparison between theory and observation.

10. Measuring the power spectrum
Pierpaoli, Scott, White (Science, 2000)
The 1 yr WMAP power spectrum

11. The cosmological parameters
Hubble constant H0 (v= H0 d)
Curvature Wk[ Cl ]
densities:
matter density Wm = rm /rcrit
baryon density Wb [ Cl ]
dark matter density Wdm = rdm /rcrit [ Cl ]
reionization/optical depth t [ Cl ]
nature of dark matter (Cold, warm or hot?) and dark energy
nature of primordial density perturbations (e.g. primordial spectral index ns)

12. The cosmological parameters from WMAP
2) Precise history of the Universe
1) The Universe is flat
tUniverse= 13.7 Gyr (+ 0.2)
trecomb=380 Kyr (+ 10)
treionization= 200 Myr
3) Fluctuations are Gaussian
(confirmation for inflation)

13. Perspectives:the Planck satellite
Higher beam
Lower noise
Polarization
Better frequency coverage
Wm within 0.5 per cent
H0 within 0.4 per cent
Wb within 0.5 per cent

14. Summary
The Cosmic Microwave Background is the relic radiation of the Big Bang
By studying the anisotropies of the CMB it is possible to determine the main cosmological parameter with the precision of a few percent
Future satellite missions (Planck) will improve these constraints by one order of magnitude

16. The Suniaev-Zeldovich clusters
Frequencies of observation e- g
cluster vc
- Thermal and kinetic signal expected
- Signal is independent of redshift
- Signal scales as ne
- Need complementary information on redshift from other data.
- Future surveys: SPT, ACT (high resolution), Planck (all sky)