First‐Year <i>Wilkinson Microwave Anisotropy Probe</i> ( <i>WMAP</i> ) Observations: Galactic Signal Contamination from Sidelobe Pickup

Abstract

Since the Galactic center is ~1000 times brighter than fluctuations in the Cosmic Microwave Background (CMB), CMB experiments must carefully account for stray Galactic pickup. We present the level of contamination due to sidelobes for the year one CMB maps produced by the WMAP observatory. For each radiometer, full 4 pi sr antenna gain patterns are determined from a combination of numerical prediction, ground-based and space-based measurements. These patterns are convolved with the WMAP year one sky maps and observatory scan pattern to generate expected sidelobe signal contamination, for both intensity and polarized microwave sky maps. Outside of the Galactic plane, we find rms values for the expected sidelobe pickup of 15, 2.1, 2.0, 0.3, 0.5 uK for K, Ka, Q, V, and W bands respectively. Except at K band, the rms polarized contamination is <<1 uK. Angular power spectra of the Galactic pickup are presented.

Keywords

Affiliated Institutions

• University of Chicago US
• National Research Council RO
• University of British Columbia CA
• Brown University US
• Science Systems and Applications (United States) US
• Goddard Space Flight Center US
• Princeton University US

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