Preprint article · Journal article
Planck intermediate results XLI. A map of lensing-induced B-modes : XLI. A map of lensing-inducedB-modes
The secondary cosmic microwave background (CMB) B-modes stem from the post-decoupling distortion of the polarization E-modes due to the gravitational lensing effect of large-scale structures. These lensing-induced B-modes constitute both a valuable probe of the dark matter distribution and an important contaminant for the extraction of the primary CMB B-modes from inflation.
Planck provides accurate nearly all-sky measurements of both the polarization E-modes and the integrated mass distribution via the reconstruction of the CMB lensing potential. By combining these two data products, we have produced an all-sky template map of the lensing-induced B-modes using a real-space algorithm that minimizes the impact of sky masks.
The cross-correlation of this template with an observed (primordial and secondary) B-mode map can be used to measure the lensing B-mode power spectrum at multipoles up to 2000. In particular, when cross-correlating with the B-mode contribution directly derived from the Planck polarization maps, we obtain lensing-induced B-mode power spectrum measurement at a significance level of 12 sigma, which agrees with the theoretical expectation derived from the Planck best-fit Lambda cold dark matter model.
This unique nearly all-sky secondary B-mode template, which includes the lensing-induced information from intermediate to small (10 less than or similar to l less than or similar to 1000) angular scales, is delivered as part of the Planck 2015 public data release. It will be particularly useful for experiments searching for primordial B-modes, such as BICEP2/Keck Array or LiteBIRD, since it will enable an estimate to be made of the lensing-induced contribution to the measured total CMB B-modes.
Language: | English |
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Publisher: | EDP Sciences |
Year: | 2016 |
Pages: | A102 |
ISSN: | 14320746 and 00046361 |
Types: | Preprint article and Journal article |
DOI: | 10.1051/0004-6361/201527932 |
ORCIDs: | 0000-0003-4213-1300 , 0000-0002-8891-0273 , Hornstrup, Allan , Linden-Vørnle, Michael and Nørgaard-Nielsen, Hans Ulrik |