Wilkinson Microwave Anisotropy Probe DR4The 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/" DR4 FarSidelobe Beam MapsCoordinate System:
Spacecraft Coordinates
Projection Type:
HEALPix, nested, res 7 (Nside=128)
Download Links:
These are resolution 7 maps of the antenna gain response over 4π steradians for each of the 10 WMAP differencing assemblies. While WMAP's optical system gain drops very rapidly when moving away from the main beam lineofsight, the emission of the extended Galactic foreground can be 1000 times brighter than the fluctuations of the CMB and can cover very large solid angles. It is therefore extremely important to fully characterize the antenna gain response. The FarSidelobe Maps are based on compilations of data from the following sources:
The gain pattern is provided in spacecraft coordinates, such that the X axis is parallel to the plane of the radiators, Z is the antisun direction of the spin axis, and Y is perpendicular to both. Gain is in dimensionless units, 4π/(beam solid angle). Positive values refer to Aside pickup, and negative values to Bside pickup. These maps are in units of directive gain, g_{i}, where i is a pixel; these are the linear units that correspond to dBi. The normalization is such that ∑_{i}(g_{i}) = 2 * Npix, or it would equal 2*Npix if the full antenna pattern were represented rather than being cut off at the radius chosen to define the main beam/farsidelobe boundary. These maps are the same as were delivered in the third data release. The boundary between the main beam lobe and the far sidelobes did not change and therefore these maps did not change. Additional Information
