WMAP CMB maps for Q, V, and W bands. The WMAP team also presented the Internal Linear Combination (ILC) by computing a weighted combination of the maps that have been band-averaged within each of the five WMAP frequency bands, all smoothed to $1\degr$ resolution (Bennett et al. 2003b). Tegmark et al. (2003) independently produced a foreground- and noise-cleaned WMAP map with W band resolution using a foreground-subtraction technique different from that of WMAP team. As compared to the combined Q, V, and W band maps, Tegmark et al.’s cleaned map (TCM) has higher signal-to-noise ratio, and can be used as an independent probe of Gaussianity.

These maps are stereographically projected on to a plane before the genus is measured. The stereographic mapping is conformal and locally preserves shapes of structures (see, e.g., Calabretta & Greisen 2002, $\S5$). The final Q, V, and W band maps have resolution of $0\fdg60$, $0\fdg45$, and $0\fdg35$ FWHM, respectively, due to the additional smoothing during the projection. We mask 23.2% of the sky that has significant foreground contamination from our Galaxy and point sources using the conservative Kp0 mask (Bennett et al. 2003b). We also remove additional 0.3% of the sky corresponding to the small 