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A demonstration of improved constraints on primordial gravitational waves with delensing

Ade, P. A. R., Ahmed, Z., Amiri, M., Anderson, A.J., Austermann, J.E., Avva, J.S., Barkats, D., Thakur, R. Basu, Beall, J.A., Bender, A.N., Benson, B.A., Bianchini, F., Bischoff, C.A., Bleem, L.E., Bock, J.J., Boenish, H., Bullock, E., Buza, V., Carlstrom, J.E., Chang, C.L., Cheshire, J.R., Chiang, H.C., Chou, T-L., Citron, R., Connors, J., Moran, C. Corbett, Cornelison, J., Crawford, T.M., Crites, A.T., Crumrine, M., Cukierman, A., de Haan, T., Dierickx, M., Dobbs, M.A., Duband, L., Everett, W., Fatigoni, S., Filippini, J.P., Fliescher, S., Gallicchio, J., George, E.M., Germaine, T.St., Goeckner-Wald, N., Goldfinger, D.C., Grayson, J., Gupta, N., Hall, G., Halpern, M., Halverson, N.W., Harrison, S., Henderson, S., Henning, J.W., Hildebrandt, S.R., Hilton, G.C., Holder, G.P., Holzapfel, W.L., Hrubes, J.D., Huang, N., Hubmayr, J., Hui, H., Irwin, K.D., Kang, J., Karkare, K.S., Karpel, E., Kefeli, S., Kernasovskiy, S.A., Knox, L., Kovac, J.M., Kuo, C.L., Lau, K., Lee, A.T., Leitch, E.?M., Li, D., Lowitz, A., Manzotti, A., McMahon, J.J., Megerian, K.G., Meyer, S.S., Millea, M., Mocanu, L.M., Moncelsi, L., Montgomery, J., Nadolski, A., Namikawa, T., Natoli, T., Netterfield, C.B., Nguyen, H.T., Nibarger, J.P., Noble, G., Novosad, V., O?Brient, R., Ogburn, R.W., Omori, Y., Padin, S., Palladino, S., Patil, S., Prouve, T., Pryke, C., Racine, B., Reichardt, C.L., Reintsema, C.D., Richter, S., Ruhl, J.E., Saliwanchik, B.R., Schaffer, K.K., Schillaci, A., Schmitt, B.L., Schwarz, R., Sheehy, C.D., Sievers, C., Smecher, G., Soliman, A., Stark, A.A., Steinbach, B., Sudiwala, R.V., Teply, G.P., Thompson, K.L., Tolan, J.E., Tucker, C., Turner, A.D., Umiltà, C., Veach, T., Vieira, J.D., Vieregg, A.G., Wandui, A., Wang, G., Weber, A.C., Whitehorn, N., Wiebe, D.V., Willmert, J., Wong, C.L., Wu, W.L.K., Yang, H., Yefremenko, V., Yoon, K.W., Young, E., Yu, C., Zeng, L. and Zhang, C. 2021. A demonstration of improved constraints on primordial gravitational waves with delensing. Physical Review D 103 (2) , 022004. 10.1103/PhysRevD.103.022004

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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 dataset collected through 2014 using the same parametric foreground modeling as in the previous analysis. From simulations, we find that the uncertainty on r is reduced by ∼ 10 % , from σ ( r ) = 0.024 to 0.022, which can be compared with a ∼ 26 % reduction obtained when using a perfect lensing template or if there were zero lensing B -modes. 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.

Item Type: Article
Date Type: Publication
Status: Published
Schools: Physics and Astronomy
Publisher: American Physical Society
ISSN: 2470-0010
Date of First Compliant Deposit: 18 February 2021
Date of Acceptance: 23 December 2020
Last Modified: 30 Jan 2022 10:55

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