CMB and foregrounds in WMAP first year data

TL;DR

This paper presents a blind multi-component analysis of WMAP 1-year data, providing a new CMB power spectrum estimate, identifying residual galactic emissions, and jointly estimating unresolved point source contributions.

Contribution

It introduces a novel application of SMICA for WMAP data, improving CMB spectrum estimation and foreground separation without prior assumptions.

Findings

CMB anisotropies are consistent with standard temperature fluctuation models

Residual galactic emission identified mainly at low galactic latitudes in Q-band

Estimated power spectrum of unresolved point sources

Abstract

We perform a blind multi-component analysis of the WMAP 1 year foreground cleaned maps using SMICA (Spectral Matching Independent Component Analysis). We provide a new estimate of the CMB power spectrum as well as the amplitude of the CMB anisotropies across frequency channels. We show that the CMB anisotropies are compatible with temperature fluctuations as expected from the standard paradigm. The analysis also allows us to identify and separate a weak residual galactic emission present significantly in the Q-band outside of the Kp2 mask limits, and mainly concentrated at low galactic latitudes. We produce a map of this residual component by Wiener filtering using estimated parameters. The level of contamination of CMB data by this component is compatible with the WMAP team estimation of foreground residual contamination. In addition, the multi-component analysis allows us to estimate jointly the power spectrum of unresolved point source emission.