First‐Year Wilkinson Microwave Anisotropy Probe ( WMAP ) Observations: Data Processing Methods and Systematic Error Limits

The WMAP satellite has now completed 3 years of observations of the cosmic microwave background radiation. The 3-year data products include several sets of full sky maps of the Stokes I, Q and U parameters in 5 frequency bands, spanning 23 to 94 GHz, and supporting items, such as beam window functions and noise covariance matrices. The processing used to produce the current sky maps and supporting products represents a significant advancement over the first year analysis, and is described herein. Improvements to the pointing reconstruction, radiometer gain modeling, window function determination and radiometer spectral noise parametrization are presented. A 1 WMAP is the result of a partnership between Princeton University and NASA’s Goddard Space Flight Center.