Galactic foreground contributions to the WMAP5 maps

Understand

We compute the cross correlation of the intensity and polarisation from the 5-year WMAP data in different sky-regions with respect to template maps for synchrotron, dust, and free-free emission.

• We derive the frequency dependence and polarisation fraction for all three components in 48 different sky regions of HEALPix (Nside=2) pixelisation.
• The anomalous emission associated with dust is clearly detected in intensity over the entire sky at the K (23 GHz) and Ka (33 GHz) WMAP bands, and is found to be the dominant foreground at low Galactic latitude, between b=-40 and b=+10.
• The synchrotron spectral index obtained from the K and Ka WMAP bands from an all-sky analysis is -3.32\pm 0.12 for intensity and -3.01\pm0.03 for the polarised intensity.