WMAP DR1 Simulated Noise Maps Description and Links

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/

Coordinate System:
Projection Type:
0.23° - 0.93° (frequency dependent)
HEALPix, nested, res 9 (Nside=512)
Download Links:

110 Monte Carlo realizations of sky maps with simulated instrument noise that include all known radiometric effects. For each realization and WMAP differencing assembly, we generate one year of simulated time-series data including white noise, 1/f noise, and all inter-channel correlations that are known to exist in the radiometers. A dipole signal is also included so that the output data may be calibrated using the flight-based algorithm. These data are then processed through the flight calibration, map-making, and filtering pipeline to generate output sky maps. As with the flight sky maps, the dipole signal is subtracted after the final calibration is applied. The maps are dominated by white, uncorrelated pixel noise. As with the flight data, the rms noise per pixel can be evaluated from N_obs via sigma = sigma_0/sqrt(N_obs), where sigma_0 for each differencing assembly is listed in the following table:

Differencing Assembly K1 Ka1 Q1 Q2 V1 V2 W1 W2 W3 W4
sigma_0 (mK) 1.42366 1.44883 2.26677 2.15567 3.28789 2.93683 5.85196 6.53276 6.88032 6.72537

The maps are provided as a collection of compressed tar files. There are sixty such tar files organized in groups of six for each WMAP differencing assembly; the first five files within a differencing assembly group contain twenty maps while the last file contains ten maps. The individual simulated noise maps within the tar files are in the same file format as the flight sky maps .

More details can be found in:

"First Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations:
Data Processing and Systematic Errors Limits," Hinshaw, et al., 2003

"First Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations:
On-Orbit Radiometer Characterization," Jarosik, et al., 2003

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Goddard Space Flight Center, National Aeronautics and Space Administration
HEASARC Director: Dr. Andrew F. Ptak
LAMBDA Director: Dr. Thomas M. Essinger-Hileman
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