The C-Band All-Sky Survey ( C-BASS ) is a high-sensitivity all-sky radio survey at an angular resolution of 45 arcmin and a frequency of 4.7 GHz .
We present a total intensity map of the North Celestial Pole ( NCP ) region of sky , above declination > +80 ^ { \circ } , which is limited by source confusion at a level of \approx 0.6 mK rms .
We apply the template-fitting ( cross-correlation ) technique to WMAP and Planck data , using the C-BASS map as the synchrotron template , to investigate the contribution of diffuse foreground emission at frequencies \sim 20 –40 GHz .
We quantify the anomalous microwave emission ( AME ) that is correlated with far-infrared dust emission .
The AME amplitude does not change significantly ( < 10 \% ) when using the higher frequency C-BASS 4.7 GHz template instead of the traditional Haslam 408 MHz map as a tracer of synchrotron radiation .
We measure template coefficients of 9.93 \pm 0.35 and 9.52 \pm 0.34 K per unit \tau _ { 353 } when using the Haslam and C-BASS synchrotron templates , respectively .
The AME contributes 55 \pm 2 \mu K rms at 22.8 GHz and accounts for \approx 60 \% of the total foreground emission .
Our results show that a harder ( flatter spectrum ) component of synchrotron emission is not dominant at frequencies \gtrsim 5 GHz ; the best-fitting synchrotron temperature spectral index is \beta = -2.91 \pm 0.04 from 4.7 to 22.8 GHz and \beta = -2.85 \pm 0.14 from 22.8 to 44.1 GHz .
Free-free emission is weak , contributing \approx 7 \mu K rms ( \approx 7 \% ) at 22.8 GHz .
The best explanation for the AME is still electric dipole emission from small spinning dust grains .