Searching for the non-Gaussian signature of the CMB secondary anisotropies
N. Aghanim, O. Forni;
AaA, 1999, 347, 409
ABSTRACT:In a first paper (Forni & Aghanim 1999), we developed several statistical discriminators to test the non-Gaussian nature of a signal.
These
tests are based on the study of the coefficients in a wavelet decomposition
basis.
In this paper, we apply them in a cosmological context, to the study of the
nature of the Cosmic Microwave Background (CMB) anisotropies.
The latter
represent the superposition of primary anisotropy imprints of the initial
density perturbations and secondary ones due to photon interactions after
recombination.
In an inflationary scenario (standard Cold Dark Matter) with Gaussian
distributed fluctuations, we study the statistical signature of the secondary
effects.
More specifically, we investigate the dominant effects arising from the
Compton scattering of CMB photons in ionised regions of the Universe: the
Sunyaev-Zel'dovich effect of galaxy clusters and the effects of a spatially inhomogeneous
re-ionisation of the Universe.
Our study specifies and predicts the non-Gaussian
signature of the secondary anisotropies induced by these scattering
effects.
We find that our statistical discriminators allow us to distinguish and
highlight the non-Gaussian signature of a process even if it is combined with a
larger Gaussian signal.
We investigate the detectability of the secondary
anisotropy non-Gaussian signature in the context of the future CMB satellites
(MAP and Planck Surveyor).
KEYWORDS: cosmology: cosmic microwave background, methods: data analysis, methods: statistical
CODE: aghanim99