Context :

Aims : The aim of the present analysis is to improve the knowledge of the statistical properties of the Galactic diffuse synchrotron emission , which constrains sensitive CMB anisotropy measurements .

Methods : We have analysed the new DRAO 1.4 GHz polarization survey together with the Stockert 1.4 GHz total intensity survey and derived the angular power spectra ( APSs ) of the total intensity , the polarized emission , and their cross-correlation for the entire surveys and for three low-intensity regions .

Results : The APSs of the diffuse synchrotron emission are modelled by power laws .
For the E and B modes , a slope of \alpha \sim [ -3.0 , -2.5 ] for the multipole range \sim [ 30 , 300 ] is found .
By the extrapolation of these results to 70 GHz , we can estimate the Galactic synchrotron contamination of CMB anisotropies , and we find results that are compatible with the ones coming from WMAP 3-yr data .
In the low-intensity regions , the cosmological primordial B mode peak at \ell \sim 100 should be clearly observable for a tensor-to-scalar ratio T / S \lower 2.0 pt \hbox { $ { > \atop \hbox { \raise 4.0 pt \hbox { $ \sim$ } } } $ } 0.5 and a synchrotron temperature spectral index \beta \sim - 3 .
Its detection is also possible for T / S \lower 2.0 pt \hbox { $ { > \atop \hbox { \raise 4.0 pt \hbox { $ \sim$ } } } $ } 0.005 and \beta \sim - 3 , in case a separation of the foreground from the CMB signal could be achieved with an accuracy of \sim 5 - 10 \% .
For the TE mode , a mask excluding |b _ { gal } | \leq 5 ^ { \circ } ( for \beta \sim - 3.0 ) or |b _ { gal } | \leq 20 ^ { \circ } ( for \beta \sim - 2.8 ) from the surveys is sufficient to render the foreground contamination negligible , thus confirming the ability of WMAP to have a clear view of the temperature-polarization correlation peak and antipeak series .

Conclusions :