0305-constrained realization and CMB S4
Last updated
Last updated
According to the simplest inflationary models, the primordial cosmological perturbations should be very nearly Gaussian.
inflationary models do exist predicting levels of non-Gaussianity that will be measurable with the Planck space mission and other new data sets.
In this paper we instead consider filling in by means of constrained Gaussian realizations. Under this approach it is assumed that the power spectrum can be characterized sufficiently well based on the data from the unmasked pixels.
CMB lensing encodes a wealth of statistical information about the entire large-scale structure (LSS) mass distribution, which is sensitive to the properties of neutrinos and dark energy.
CMB lensing distortions obscure our view of the primordial Universe, limiting our power to constrain inflationary signals; removing this lensing noise more cleanly brings the early Universe and any inflationary signatures into sharper focus.
To date, all maps of the lensing field have been constructed using the quadratic estimator by arXiv:astro-ph/0111606 [astro-ph].
It is important to have relatively high-angular resolution maps in order to obtain the small-scale E and B fluctuations needed for the EB quadratic lensing estimator. As shown in Figure 56, quadratic EB lens reconstruction requires high-fidelity measurements of the E and B polarization fields on a variety of angular scales.
However, the extragalactic sources and tSZ clusters that can cause large sources of bias in temperature-based CMB lensing estimates are expected to be nearly unpolarized and therefore not a concern for polarization-based lensing estimates
The main beam systematics that affect CMB measurements are commonly described by differential gain, differential beamwidth, differential ellipticity, and differential pointing and rotation.
Map-making is the stage of the analysis when the major compression of the time-ordered data happens and some estimate of the sky signal is produced at each observing frequency.
SMICA: semi-blind method
The idea of Independent Component Analysis (ICA) is to blindly recover the full mixing matrix A by using the independence property of the different components.
For science on smaller angular scales, the presence of polarized extragalactic radio and infrared sources constitutes an additional source of contamination, which must be removed with a combination of masking or subtracting individual sources, and modeling residuals at the power-spectrum level.