WMAP DR1 Smoothed I Maps (per frequency)
The data made available through this page has been updated. The most recent version of this data may be accessed through https://lambda.gsfc.nasa.gov/product/wmap/current/
HEALPix, nested, res 9 (Nside=512)
These maps result from smoothing the I Maps to a common resolution of 1 degree. Smoothing is performed in Fourier space by transforming the map to a_lm's, up to the Nyquist frequency of the map, applying a window function determined by the smoothing kernel, then transforming back to pixel space. The smoothing window function is computed from the ratio of the desired output 1 degree FWHM Gaussian window function and the beam transfer function appropriate to each WMAP frequency bandpass.
Note that the instrument noise and sky signal are correlated between neighboring pixels in these maps. These maps are not intended for use in CMB studies, but rather for cases such as foreground analyses where a common resolution among maps is useful.
Pixel temperatures are provided in thermodynamic units, in mK. Because of the difficulty in associating a noise with each pixel, the effective number of observations (N_obs) has been set to 1.0 for all pixels.
More details can be found in: