The cross correlation of the ABS and ACT maps
  One of the most important checks for systematic errors in CMB studies is the
cross correlation of maps made by independent experiments. In this paper we
report on the cross correlation between maps from the Atacama B-mode Search
(ABS) and Atacama Cosmology Telescope (ACT) experiments in both temperature and
polarization. These completely different measurements have a clear correlation
with each other and with the Planck satellite in both the EE and TE spectra at
$\ell<400$ over the roughly $1100$ deg$^2$ common to all three. The TB, EB, and
BB cross spectra are consistent with noise. Exploiting such cross-correlations
will be important for future experiments operating in Chile that aim to probe
the $30<\ell<8,000$ range.
