1. Constraints on Primordial Gravitational Waves Using Planck, WMAP, and New BICEP2/Keck Observations through the 2015 Season.
- Author
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Ade PAR, Ahmed Z, Aikin RW, Alexander KD, Barkats D, Benton SJ, Bischoff CA, Bock JJ, Bowens-Rubin R, Brevik JA, Buder I, Bullock E, Buza V, Connors J, Cornelison J, Crill BP, Crumrine M, Dierickx M, Duband L, Dvorkin C, Filippini JP, Fliescher S, Grayson J, Hall G, Halpern M, Harrison S, Hildebrandt SR, Hilton GC, Hui H, Irwin KD, Kang J, Karkare KS, Karpel E, Kaufman JP, Keating BG, Kefeli S, Kernasovskiy SA, Kovac JM, Kuo CL, Larsen NA, Lau K, Leitch EM, Lueker M, Megerian KG, Moncelsi L, Namikawa T, Netterfield CB, Nguyen HT, O'Brient R, Ogburn RW, Palladino S, Pryke C, Racine B, Richter S, Schillaci A, Schwarz R, Sheehy CD, Soliman A, St Germaine T, Staniszewski ZK, Steinbach B, Sudiwala RV, Teply GP, Thompson KL, Tolan JE, Tucker C, Turner AD, Umiltà C, Vieregg AG, Wandui A, Weber AC, Wiebe DV, Willmert J, Wong CL, Wu WLK, Yang H, Yoon KW, and Zhang C
- Abstract
We present results from an analysis of all data taken by the bicep2/Keck CMB polarization experiments up to and including the 2015 observing season. This includes the first Keck Array observations at 220 GHz and additional observations at 95 and 150 GHz. The Q and U maps reach depths of 5.2, 2.9, and 26 μK_{CMB} arcmin at 95, 150, and 220 GHz, respectively, over an effective area of ≈400 square degrees. The 220 GHz maps achieve a signal to noise on polarized dust emission approximately equal to that of Planck at 353 GHz. We take auto and cross spectra between these maps and publicly available WMAP and Planck maps at frequencies from 23 to 353 GHz. We evaluate the joint likelihood of the spectra versus a multicomponent model of lensed-ΛCDM+r+dust+synchrotron+noise. The foreground model has seven parameters, and we impose priors on some of these using external information from Planck and WMAP derived from larger regions of sky. The model is shown to be an adequate description of the data at the current noise levels. The likelihood analysis yields the constraint r_{0.05}<0.07 at 95% confidence, which tightens to r_{0.05}<0.06 in conjunction with Planck temperature measurements and other data. The lensing signal is detected at 8.8σ significance. Running a maximum likelihood search on simulations we obtain unbiased results and find that σ(r)=0.020. These are the strongest constraints to date on primordial gravitational waves.
- Published
- 2018
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