Template fitting of WMAP 7-year data: anomalous dust or flattening
  synchrotron emission?
  Anomalous microwave emission at 20-40 GHz has been detected across our
Galactic sky. It is highly correlated with thermal dust emission and hence it
is thought to be due to spinning dust grains. Alternatively, this emission
could be due to synchrotron radiation with a flattening (hard) spectral index.
We cross-correlate synchrotron, free-free and thermal dust templates with the
WMAP 7-year maps using synchrotron templates at both 408 MHz and 2.3 GHz to
assess the amount of flat synchrotron emission that is present, and the impact
that this has on the correlations with the other components. We find that there
is only a small amount of flattening visible in the synchrotron spectral
indices by 2.3 GHz, of around \Delta \beta ~ 0.05, and that the significant
level of dust-correlated emission in the lowest WMAP bands is largely
unaffected by the choice of synchrotron template, particularly at high
latitudes (it decreases by only ~7 per cent when using 2.3 GHz rather than 408
MHz). This agrees with expectation if the bulk of the anomalous emission is
generated by spinning dust grains.
