Galactic foreground contributions to the WMAP5 maps
  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. The polarisation fraction of the
synchrotron is constant in frequency and increases with latitude from ~5% near
the Galactic plane up to ~40% in some regions at high latitude; the average
value for |b|<20 is 8.6\pm1.7 (stat) \pm0.5 (sys) % while for |b|>20 it is
19.3\pm0.8 (stat) \pm 0.5 (sys) %. Anomalous dust and free-free emission appear
to be relatively unpolarised...[Abridged]...the average polarisation fraction
of dust-correlated emission at K-band is 3.2\pm0.9 (stat) \pm 1.5 (sys) %, or
less than 5% at 95% confidence. When comparing real data with simulations, 8
regions show a detected polarisation above the 99th percentile of the
distribution from simulations with no input foreground polarisation, 6 of which
are detected at above 2sigma and display polarisation fractions between 2.6%
and 7.2%, except for one anomalous region, which has 32\pm12%. The dust
polarisation values are consistent with the expectation from spinning-dust
emission, but polarised dust emission from magnetic-dipole radiation cannot be
ruled out. Free-free emission was found to be unpolarised with an upper limit
of 3.4% at 95% confidence.
