Cosmology with the CMB temperature-polarization correlation
  We demonstrate that the cosmic microwave background (CMB)
temperature-polarization cross-correlation provides accurate and robust
constraints on cosmological parameters. We compare them with the results from
temperature or polarization and investigate the impact of foregrounds, cosmic
variance, and instrumental noise. This analysis makes use of the Planck
high-multipole HiLLiPOP likelihood based on angular power spectra, which takes
into account systematics from the instrument and foreground residuals directly
modelled using Planck measurements. The temperature-polarization correlation
(TE) spectrum is less contaminated by astrophysical emissions than the
temperature power spectrum (TT), allowing constraints that are less sensitive
to foreground uncertainties to be derived. For {\Lambda}CDM parameters, TE
gives very competitive results compared to TT. For basic {\Lambda}CDM model
extensions (such as AL, {\Sigma}m{\nu}, or Neff ), it is still limited by the
instrumental noise level in the polarization maps.
