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 ( N _ { \mathrm { side } } = 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 ^ { \circ } and b = +10 ^ { \circ } .
The synchrotron spectral index obtained from the K and Ka WMAP bands from an all-sky analysis is \beta = -3.32 \pm 0.12 for intensity and \beta = -3.01 \pm 0.03 for the polarised intensity .

The polarisation fraction of the synchrotron is constant in frequency and increases with latitude from \approx 5 \% near the Galactic plane up to \approx 40 \% in some regions at high latitude ; the average value for |b| < 20 ^ { \circ } is 8.6 \pm 1.7 \textrm { ( stat ) } \pm 0.5 \textrm { ( sys ) } \% while for |b| > 20 ^ { \circ } it is 19.3 \pm 0.8 \textrm { ( stat ) } \pm 0.5 \textrm { ( sys ) } \% .
Anomalous dust and free-free emission appear to be relatively unpolarised .
Monte carlo simulations showed that there were biases of the method due to cross-talk between the components , at up to \approx 5 \% in any given pixel , and \approx 1.5 \% on average , when the true polarisation fraction is low ( a few per cent or less ) .
Nevertheless , the average polarisation fraction of dust-correlated emission at K-band is 3.2 \pm 0.9 \textrm { ( stat ) } \pm 1.5 \textrm { ( 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 2 \sigma and display polarisation fractions between 2.6 \% and 7.2 \% , except for one anomalous region , which has 32 \pm 12 \% .
The dust polarisation values are consistent with the expectation from spinning-dust emission , but polarised dust emission from magnetic-dipole radiation can not be ruled out .
Free-free emission was found to be unpolarised with an upper limit of 3.4 \% at 95 % confidence .