Journal Article

Foreground maps in <i>Wilkinson Microwave Anisotropy Probe</i> frequency bands

Tuhin Ghosh, Jacques Delabrouille, Mathieu Remazeilles, Jean-François Cardoso and Tarun Souradeep

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 412, issue 2, pages 883-899
Published in print April 2011 | ISSN: 0035-8711
Published online March 2011 | e-ISSN: 1365-2966 | DOI:
Foreground maps in Wilkinson Microwave Anisotropy Probe frequency bands

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This paper provides full sky maps of foreground emission in all Wilkinson Microwave Anisotropy Probe (WMAP) channels, with very low residual contamination from the cosmic microwave background (CMB) anisotropies and controlled level of instrumental noise. Foreground maps are obtained by subtraction of a properly filtered CMB map, obtained from linear combinations of needlet-based representations of all WMAP observations and of a map. The error in the reconstructed foreground maps on large scales is significantly lower than the original error due to CMB contamination, while remaining of the order of the original WMAP noise on small scales. The level of the noise is estimated, which permits to implement local filters for maximizing the local signal-to-noise ratio. An example of such filtering, which reduces the small-scale noise using latitude-dependent filters, is implemented. This enhances significantly the contrast of galactic emission, in particular on intermediate angular scales and at intermediate galactic latitude. The clean WMAP foreground maps can be used to study the galactic interstellar medium, in particular for the highest frequency channels for which the proper subtraction of CMB contamination is mandatory. The foregrounds maps can be downloaded from a dedicated website.

Keywords: radiation mechanism: general; cosmic background radiation; cosmology: observations; diffuse radiation; radio continuum: ISM

Journal Article.  6784 words.  Illustrated.

Subjects: Astronomy and Astrophysics

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