Assessing Consistency Between WMAP 9-year and Planck 2015 Temperature
  Power Spectra
  We perform a comparison of WMAP 9-year (WMAP9) and Planck 2015 cosmic
microwave background (CMB) temperature power spectra across multipoles
$30\leq\ell\leq1200$. We generate simulations to estimate the correlation
between the two datasets due to cosmic variance from observing the same sky. We
find that their spectra are consistent within $1\sigma$. While we do not
implement the optimal "$C^{-1}$" estimator on WMAP maps as in the WMAP9
analysis, we demonstrate that the change of pixel weighting only shifts our
results at most at the $0.66\sigma$ level. We also show that changing the
fiducial power spectrum for simulations only impacts the comparison at around
$0.1\sigma$ level. We exclude $\ell<30$ both because WMAP9 data were included
in the Planck 2015 $\ell<30$ analysis, and because the cosmic variance
uncertainty on these scales is large enough that any remaining systematic
difference between the experiments is extremely unlikely to affect cosmological
constraints. The consistency shown in our analysis provides high confidence in
both the WMAP9 temperature power spectrum and the overlapping multipole region
of Planck 2015's, virtually independent of any assumed cosmological model. Our
results indicate that cosmological model differences between Planck and WMAP do
not arise from measurement differences, but from the high multipoles not
measured by WMAP.
