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A Demonstration of Improved Constraints on Primordial Gravitational Waves with Delensing
- Source :
- Phys. Rev. D 103, 022004 (2021)
- Publication Year :
- 2020
-
Abstract
- We present a constraint on the tensor-to-scalar ratio, $r$, derived from measurements of cosmic microwave background (CMB) polarization $B$-modes with "delensing," whereby the uncertainty on $r$ contributed by the sample variance of the gravitational lensing $B$-modes is reduced by cross-correlating against a lensing $B$-mode template. This template is constructed by combining an estimate of the polarized CMB with a tracer of the projected large-scale structure. The large-scale-structure tracer used is a map of the cosmic infrared background derived from Planck satellite data, while the polarized CMB map comes from a combination of South Pole Telescope, BICEP/Keck, and Planck data. We expand the BICEP/Keck likelihood analysis framework to accept a lensing template and apply it to the BICEP/Keck data set collected through 2014 using the same parametric foreground modelling as in the previous analysis. From simulations, we find that the uncertainty on $r$ is reduced by $\sim10\%$, from $\sigma(r)$= 0.024 to 0.022, which can be compared with a $\sim26\%$ reduction obtained when using a perfect lensing template. Applying the technique to the real data, the constraint on $r$ is improved from $r_{0.05} < 0.090$ to $r_{0.05} < 0.082$ (95\% C.L.). This is the first demonstration of improvement in an $r$ constraint through delensing.<br />Comment: 23 pages, 11 figures; match published version
- Subjects :
- Astrophysics - Cosmology and Nongalactic Astrophysics
Subjects
Details
- Database :
- arXiv
- Journal :
- Phys. Rev. D 103, 022004 (2021)
- Publication Type :
- Report
- Accession number :
- edsarx.2011.08163
- Document Type :
- Working Paper
- Full Text :
- https://doi.org/10.1103/PhysRevD.103.022004