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Legacy Archive for Microwave Background Data Analysis

Wilkinson Microwave Anisotropy Probe

The data made available through this page has been updated. The most recent version of this data may be accessed through /product/map/current/

Product Name
Smoothed Stokes I Sky Maps Per Frequency Band
Mission
WMAP
Coord. System
Galactic
Projection Type
HEALPix, nested, res 9 (Nside=512)
Resolution
1° (frequency dependent)

Description

As part of the foreground analysis, the Stokes I frequency band maps were smoothed to 1° resolution. These smoothed maps play a part in creating a CMB map used in the MEM and ILC foreground modeling efforts discussed in Hinshaw, et.al., 2006; see that paper for details.

WMAP maps are stored in FITS binary table extensions. The maps are stored in the first extension in a file; the format of this table depends upon whether polarization maps have been included in the file. Some files also contain the polarization covariance matrices for the maps; if supplied these matrices are stored in a second binary table extension.

As previously stated, the first FITS extension contains the maps. These maps are in a nested HEALPix format, with each row representing a single pixel. There are either four or two columns depending upon whether or not polarization maps are included; these columns are:

TEMPERATURE The Stokes I, or temperature, measurement in mK (thermodynamic).
Q_POLARISATION The Stokes Q polarization measurement in mK (thermodynamic).
U_POLARISATION The Stokes U polarization measurement in mK (thermodynamic).
N_OBS The effective number of observations.

The column names were selected to be compatible with existing HEALPix software. The TEMPERATURE and N_OBS columns are the only columns that exist in files that do not contain polarization maps.

Additional Information

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  • NASA Official: Dr. Gary F. Hinshaw
  • Page Updated: Friday, 18-Apr-2008
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