François Bouchet

CMB Polarization can constrain cosmology better than CMB temperature

We demonstrate that for a cosmic variance limited experiment, CMB E polarization alone places stronger constraints on cosmological parameters than CMB temperature. For example, we show that EE can constrain parameters better than TT by up to a factor 2.8 when a multipole range of l=30-2500 is considered. We expose the physical effects at play behind this remarkable result and study how it depends on the multipole range included in the analysis. In most relevant cases, TE or EE surpass the TT based cosmological constraints. This result is important as the small scale astrophysical foregrounds are expected to have a much reduced impact on polarization, thus opening the possibility of building cleaner and more stringent constraints of the LCDM model. This is relevant specially for proposed future CMB satellite missions, such as CORE or PRISM, that are designed to be cosmic variance limited in polarization till very large multipoles. We perform the same analysis for a Planck-like experiment, and conclude that even in this case TE alone should determine the constraint on

Non Gaussianity and Minkowski Functionals: forecasts for Planck

Omega_ch^2

Angular Correlation Functions for Models with Logarithmic Oscillations

better than TT by 15%, while determining

Fluctuation Analysis of the Far-Infrared Background - Information from the Confusion

Omega_bh^2

The Komatsu Spergel Wandelt estimator for oscillations in the cosmic microwave background bispectrum

,

Cosmic microwave background constraints in light of priors over reionization histories

n_s

Probing inflation with cosmic microwave background polarization: the weak lensing effect on the covariance of cosmic microwave background spectra

and

Planck high-frequency instrument

theta

The Planck mission

with comparable accuracy. Finally, we explore a few classical extensions of the LCDM model and show again that CMB polarization alone provides more stringent constraints than CMB temperature in case of a cosmic variance limited experiment.

The KSW estimator for oscillations in the CMB bispectrum

We study Minkowski Functionals as probes of primordial non-Gaussianity in the Cosmic Microwave Background, specifically for the estimate of the primordial `local bi-spectrum parameter f_NL, with instrumental parameters which should be appropriate for the Planck experiment. We use a maximum likelihood approach, which we couple with various filtering methods and test thoroughly for convergence. We included the effect of inhomogeneous noise as well as astrophysical biases induced by point sources and by the contamination from the Galaxy. We find that, when Wiener filtered maps are used (rather than simply smoothed with Gaussian), the expected error on the measurement of f_NL should be as small as Delta f_NL simeq 10 when combining the 3 channels at 100, 143 and 217 GHz in the Planck extended mission setup. This result is fairly insensitive to the non homogeneous nature of the noise, at least for realistic hit-maps expected from Planck. We then estimate the bias induced on the measurement of f_NL by point sources in those 3 channels. With the appropriate masking of the bright sources, this bias can be reduced to a negligible level in the 100 and 143 GHz channels. It remains significant in the 217 GHz channel, but can be corrected for. The galactic foreground biases are quite important and present a complex dependence on sky coverage: making them negligible will depend strongly on the quality of the component separation methods.