WMAP 
Wilkinson Microwave Anisotropy ProbeProduct Name
Inverse Covariance Matrices
Mission
WMAP
Coord. System
Galactic
Projection Type
HEALPix, nested, Res 4/NSide=16
Description The inverse covariance (N^{1}) matrices supplied with the higher resolution maps do not fullly characterize the pixeltopixel noise in the res 4 maps. Therefore a more accurate and much larger inverse covariance matrix is supplied for each map as a separate product. These are supplied in one of two forms:
All the inverse covariance matrices have had σ_{0}^{2} divided out of them. These factors may be found in skymap_info.cfm. The elements corresponding to the Galatic plane pixels as defined by the processing mask were set to zero. Therefore, the matrices as supplied are singular. To make them nonsingular, the row and the column corresponding to each zero element of the diagonal need to be deleted. The matrices include a contribution due to uncertainty in the loss imbalance coefficients in each differencing assembly (Jarosik et al. 2010). In previous releases, this uncertainty was fully marginalizedequivalent to assuming no information about these coefficients. In the latest release of the matrices for raw Stokes Q and U maps (those without foreground cleaning), a true 1σ uncertainty was incorporated into this term. Additional Information
