1. The Cosmic Microwave Background
Lecture 1
Elena Pierpaoli

2. (Cosmic Microwave Background)
Brief History of time

3. 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.

4. Space Missions PLANCK: Smaller beam Lower noise Polarization
Better frequency coverage

5. Measuring the Fundamental Properties of the Universe
Observables
Radiation
Matter
SDSS slice
CMB - Cosmic Microwave Background
(Temperature and Polarization)
DT(q,f) = S al,m Yl,m (q,f)
cl = Sm |al,m|2
d (x) = dr/r (x)
d (k) = FT[d (x)]
P(k) = < |d (k)|2>
Pgal(k) = b2 P(k)
bias

6. The power spectrum
Nolta et al 08

7. The decomposition of the CMB spectrum
Challinor 04

8. Evolution equations Photons Cold dark amtter Baryons metric
Massive neutrinos
Massless neutrinos

9. Evolution of fluctuations
Ma & Bertschinger 95

10. Line of sight approach
Seljak & Zaldarriaga 06

11. Polarization
Due to parity symmetry of the density field, scalar perturbations
Have U=0, and hence only produce E modes.

12. Scattering and polarization
If there is no U mode to start with, scattering does not generate it. No B mode is generated.
Scattering sources polarization through the quadrupole.

13. Tensor modes Parity and rotation symmetry are no longer satisfied.
B modes could be generated, along with T and E.

14. The tensor modes expansion
Scattering only produces E modes, B
Are produced through coupling with E
And free streaming.

15. Power spectra for scalar and tensor perturbations
Tensor to scalar ratio r=1

16. Effect of parameters
Effect of various parameters on the T and P spectrum

17. 1)Neutrino mass: Physical effects
on fluctuations
Fluctuation on scale  enters the horizon
Neutrinos free-stream
Neutrinos do not free-stream
(I.e. behave like Cold Dark Matter)
Derelativization
Expan. factor a
Recombination
Radiation dominated
Matter dominated
heavy
light
(T=0.25 eV)
on expansion
change the expansion rate
Change matter-radiation equivalence (but not recombination)

18. 2) The relativistic energy density Nn
Nn = (rrad - rg) / r1n
Expan. factor a
Recombination
Radiation dominated
Matter dominated
3
>3
Effects:
change the expansion rate
Change matter-radiation equivalence (but not the radiation temperature, I.e. not recombination)
Model for:
neutrino asymmetry
other relativistic particles
Gravitational wave contribution
(Smith, Pierpaoli, Kamionkowski 2006)
CONSTRAINTS:
Before WMAP: N <17
After WMAP:N< 6.6
(Pierpaoli MNRAS 2003)

19. Neutrino species
Bell, Pierpaoli, Sigurdson 06

20. Neutrino interactions