A Demonstration of Improved Constraints on Primordial Gravitational Waves with Delensing
Creators: name: BICEP/Keck
name: Collaborations, SPTpol
name: :
name: Ade, P. A. R.
name: Ahmed, Z.
name: Amiri, M.
name: Anderson, A. J.
name: Austermann, J. E.
name: Avva, J. S.
name: Barkats, D.
name: Thakur, R. Basu
name: Beall, J. A.
name: Bender, A. N.
name: Benson, B. A.
name: Bianchini, F.
name: Bischoff, C. A.
name: Bleem, L. E.
name: Bock, J. J.
name: Boenish, H.
name: Bullock, E.
name: Buza, V.
name: Carlstrom, J. E.
name: Chang, C. L.
name: Cheshire, J. R.
name: Chiang, H. C.
name: Chou, T-L.
name: Citron, R.
name: Connors, J.
name: Moran, C. Corbett
name: Cornelison, J.
name: Crawford, T. M.
name: Crites, A. T.
name: Crumrine, M.
name: Cukierman, A.
name: de Haan, T.
name: Dierickx, M.
name: Dobbs, M. A.
name: Duband, L.
name: Everett, W.
name: Fatigoni, S.
name: Filippini, J. P.
name: Fliescher, S.
name: Gallicchio, J.
name: George, E. M.
name: Germaine, T. St.
name: Goeckner-Wald, N.
name: Goldfinger, D. C.
name: Grayson, J.
name: Gupta, N.
name: Hall, G.
name: Halpern, M.
name: Halverson, N. W.
name: Harrison, S.
name: Henderson, S.
name: Henning, J. W.
name: Hildebrandt, S. R.
name: Hilton, G. C.
name: Holder, G. P.
name: Holzapfel, W. L.
name: Hrubes, J. D.
name: Huang, N.
name: Hubmayr, J.
name: Hui, H.
name: Irwin, K. D.
name: Kang, J.
name: Karkare, K. S.
name: Karpel, E.
name: Kefeli, S.
name: Kernasovskiy, S. A.
name: Knox, L.
name: Kovac, J. M.
name: Kuo, C. L.
name: Lau, K.
name: Lee, A. T.
name: Leitch, E. M.
name: Li, D.
name: Lowitz, A.
name: Manzotti, A.
name: McMahon, J. J.
name: Megerian, K. G.
name: Meyer, S. S.
name: Millea, M.
name: Mocanu, L. M.
name: Moncelsi, L.
name: Montgomery, J.
name: Nadolski, A.
name: Namikawa, T.
name: Natoli, T.
name: Netterfield, C. B.
name: Nguyen, H. T.
name: Nibarger, J. P.
name: Noble, G.
name: Novosad, V.
name: O'Brient, R.
name: Ogburn, R. W.
name: Omori, Y.
name: Padin, S.
name: Palladino, S.
name: Patil, S.
name: Prouve, T.
name: Pryke, C.
name: Racine, B.
name: Reichardt, C. L.
name: Reintsema, C. D.
name: Richter, S.
name: Ruhl, J. E.
name: Saliwanchik, B. R.
name: Schaffer, K. K.
name: Schillaci, A.
name: Schmitt, B. L.
name: Schwarz, R.
name: Sheehy, C. D.
name: Sievers, C.
name: Smecher, G.
name: Soliman, A.
name: Stark, A. A.
name: Steinbach, B.
name: Sudiwala, R. V.
name: Teply, G. P.
name: Thompson, K. L.
name: Tolan, J. E.
name: Tucker, C.
name: Turner, A. D.
name: Umiltà, C.
name: Veach, T.
name: Vieira, J. D.
name: Vieregg, A. G.
name: Wandui, A.
name: Wang, G.
name: Weber, A. C.
name: Whitehorn, N.
name: Wiebe, D. V.
name: Willmert, J.
name: Wong, C. L.
name: Wu, W. L. K.
name: Yang, H.
name: Yefremenko, V.
name: Yoon, K. W.
name: Young, E.
name: Yu, C.
name: Zeng, L.
name: Zhang, C.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: 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 $σ(r)$= 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 $r_{0.05} &lt; 0.090$ to $r_{0.05} &lt; 0.082$ (95\% C.L.). This is the first demonstration of improvement in an $r$ constraint through delensing.
description: 23 pages, 11 figures; match published version