1. Planck 2013 results, implications for cosmology
Michele Liguori
Department of Physics and Astronomy, University of Padova
On behalf of the Planck collaboration

2. CMB basics
In big bang cosmology the Universe is initially in a hot and dense state
Free electrons and nuclei interact with photons via Compton scattering
As the Universe cools down, electrons combine with photons to form Hydrogen atoms (recombination)  matter-radiation decoupling
Time of decoupling ~ yrs. Temperature at decoupling ~ 3000 K.
Due to Universe expansion the CMB has today a blackbody spectrum with color temperature T ~ 2.7 K
The Early Universe is nearly, but not perfectly homogeneous and isotropic. Matter and radiation accrete onto overdense regions  anisotropies in the CMB spatial temperature distribution
M. Liguori   ”Planck 2013 results, implications for cosmology"

3. Initial conditions Inhomogeneous Homogeneous INFLATION x 100,000
M. Liguori   ”Planck 2013 results, implications for cosmology"

4. Generation of temperature anisotropies
On large scales:
density fluctuations at last scattering + gravitational redshift (SW effect)
On intermediate scales:
acoustic oscillations
On small scales:
Damping due to photon free streaming (Silk damping)
M. Liguori   ”Planck 2013 results, implications for cosmology"

5. The CMB as seen by Planck
M. Liguori   ”Planck 2013 results, implications for cosmology"

6. The power spectrum
M. Liguori   ”Planck 2013 results, implications for cosmology"

7. Sensitivity instrumental noise beam signal sky coverage
Even for an ideal noiseless experiment error bars are not 0 due to
cosmic variance
An experiment is:
Cosmic variance dominated where the error budget is dominated by
the cosmic variance term (instrumental noise is negligible, low l)
Signal dominated where Cl > Nl (low l)
Noise dominated when Nl > Cl (high l)
M. Liguori   ”Planck 2013 results, implications for cosmology"

8. Planck, main features
Large frequency coverage: 30, 44, 70, 100, 143, 217, 353, 545, 857 Ghz . Allows accurate separation of galactic and extragalactic foregrounds
Two different instruments: LFI radiometers in the [30 Ghz; 70 Ghz] range, HFI bolometers in the [100 Ghz; 857 Ghz] range. Allows tight control of systematics
Full sky coverage
High sensitivity: signal dominated for l<2000, cosmic variance dominated for l<1500
High angular resolution: between 14 and 5 arcmin for cosmologically most relevant channels
M. Liguori   ”Planck 2013 results, implications for cosmology"

9. M. Liguori   ”Planck 2013 results, implications for cosmology"

10. COBE, WMAP, Planck Npix ~ 104 FWHM ~ 7o lmax ~ 30 Npix ~ 3×106
FWHM ~ 12 arcmin
lmax ~ 1000
Npix ~ 5×107
FWHM ~ 5 arcmin
lmax ~ 3000
Planck
M. Liguori   ”Planck 2013 results, implications for cosmology"

11. Frequency maps “cleaning + coadding”
M. Liguori   ”Planck 2013 results, implications for cosmology"

12. Planck CMB power spectrum
M. Liguori   ”Planck 2013 results, implications for cosmology"

13. WMAP+Planck+ACT+SPT
M. Liguori   ”Planck 2013 results, implications for cosmology"

14. Cosmological parameters
A 6-parameters LCDM model allows a very good fit of the data:
Baryon density: Wb
Matter density: Wm
Acoustic scale (angular size): qMC
Optical depth to reionization: t
Amplitude of primordial scalar fluctuations: As
Scalar Spectral index: ns
M. Liguori   ”Planck 2013 results, implications for cosmology"

15. Effect of changing parameters on Cl
M. Liguori   ”Planck 2013 results, implications for cosmology"

16. Planck parameters measurements
M. Liguori   ”Planck 2013 results, implications for cosmology"

17. Extensions to the “minimal” model
M. Liguori   ”Planck 2013 results, implications for cosmology"

18. More extensions…
M. Liguori   ”Planck 2013 results, implications for cosmology"

19. CMB lensing
Large scale structure deflects the trajectory of CMB photons
through gravitational lensing
Deflection angle
CMB lensing potential
Can build quadratic estimators of the lensing potential, exploiting the
breaking of isotropy i.e. the appearance of off-diagonal term in the alm
covariance matrix (equivalently, the coupling between T and grad T )
The lensing potential depends on cosmological parameters and probes
completely different redshifts w.r.t primary anisotropies!
Lensing also affects the Cl directly (“redistribution of scales” and damping)
M. Liguori   ”Planck 2013 results, implications for cosmology"

20. Planck lensing measurements
M. Liguori   ”Planck 2013 results, implications for cosmology"

21. Neutrino masses Cosmological measurements constrain
Massive neutrinos below free streaming scale do not cluster, thus
the gravitational potential decays at small scales during matter domination
in this case
Main effect on CMB: changes in lensing (less smoothing of peaks, less
power in lensing likelihood at L > 10)
Without lensing the constraining power of CMB alone is small. Previous
measurements used generally a combination of CMB and LSS data
Planck +WMAP low-l
M. Liguori   ”Planck 2013 results, implications for cosmology"

22. The bispectrum l3 l2 l1 lmax lmax
M. Liguori   ”Planck 2013 results, implications for cosmology"

23. Bispectrum definitionl3 l2 l2 l3 l1 l1
M. Liguori   ”Planck 2013 results, implications for cosmology"

24. Bispectrum definitionl3
squeezed l2 l1
M. Liguori   ”Planck 2013 results, implications for cosmology"

25. Bispectrum definitionl3
squeezed
equilateral l2 l1
M. Liguori   ”Planck 2013 results, implications for cosmology"

26. Bispectrum definitionl3
squeezed
equilateral l2
flat
flat l1
M. Liguori   ”Planck 2013 results, implications for cosmology"

27. Shapes Local Equilateral Orthog. ISW-l.
M. Liguori   ”Planck 2013 results, implications for cosmology"

28. fNL from Planck data SMICA SEVEM NILC C-R
M. Liguori   ”Planck 2013 results, implications for cosmology"

29. The Planck bispectrum NILC SEVEM SMICA SMICA WAVES SMICA POLYS
M. Liguori   ”Planck 2013 results, implications for cosmology"

30. M. Liguori   ”Planck 2013 results, implications for cosmology”

31. Conclusions
Planck is a full-sky CMB satellite characterized by unprecedented sensitivity
and frequency coverage
We summarized some of the main cosmological results of the first Planck data
release, including:
High precision measurements of cosmological parameters, in very good
agreement with the standard 6-parameters LCDM model
25s detection of CMB lensing and lensing potential reconstruction
Constraints on neutrino masses
High precision constraints on primordial non-Gaussianity and bispectrum
reconstruction
The future:
Twice as many data in the full mission compared to the nominal mission
Polarization!!
M. Liguori   ”Planck 2013 results, implications for cosmology"