Wilkinson Microwave Anisotropy Probe

Product Name
Maximum Entropy Method Maps
Coord. System
Projection Type
HEALPix, nested, res 7 (Nside=128)


The Maximum Entropy Method (MEM) is used to derive all-sky maps of the synchrotron, free-free, spinning dust, and thermal dust foregrounds at each of the 5 WMAP frequencies. Using the Smoothed I Maps minus the ILC map as input, representations of each of the foregrounds are fit to each pixel independently. The synchrotron, free-free and dust spectral indices are assumed to be constant over the sky. The shape of the spinning dust spectrum is also assumed constant, but the model includes a frequency scale factor for the spinning dust spectrum for pixels where the spinning dust prior is brighter than 0.1 mK. The MEM technique fits for the separate components and the frequency scaling of the spinning dust spectrum by minimizing an entropy functional using priors based on the listed templates:

Component Prior
Synchrotron Haslam 408 MHz
Free Free Scattering corrected, extinction corrected H-alpha Map
Spinning Dust SFD Dust Map
Thermal Dust FDS Map

Foreground maps of each component for each frequency band are supplied. Note that the model temperatures are in mK, antenna temperature, rather than in thermodynamic units. A map of the peak frequency of spinning dust emission is also supplied.

Additional Information

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A service of the HEASARC and of the Astrophysics Science Division at NASA/GSFC
Goddard Space Flight Center, National Aeronautics and Space Administration
HEASARC Director: Dr. Alan P. Smale
LAMBDA Director: Dr. Eric R. Switzer
NASA Official: Dr. Eric R. Switzer
Web Curator: Mr. Michael R. Greason