A Caltech Library Service

Improved Constraints on Primordial Gravitational Waves using Planck, WMAP, and BICEP/Keck Observations through the 2018 Observing Season

Ade, P. A. R. and Ahmed, Z. and Amiri, M. and Barkats, D. and Basu Thakur, R. and Bischoff, C. A. and Beck, D. and Bock, J. J. and Boenish, H. and Bullock, E. and Buza, V. and Cheshire, J. R. and Connors, J. and Cornelison, J. and Crumrine, M. and Cukierman, A. and Denison, E. V. and Dierickx, M. and Duband, L. and Eiben, M. and Fatigoni, S. and Filippini, J. P. and Fliescher, S. and Goeckner-Wald, N. and Goldfinger, D. C. and Grayson, J. and Grimes, P. and Hall, G. and Halal, G. and Halpern, M. and Hand, E. and Harrison, S. and Henderson, S. and Hildebrandt, S. R. and Hilton, G. C. and Hubmayr, J. and Hui, H. and Irwin, K. D. and Kang, J. and Karkare, K. S. and Karpel, E. and Kefeli, S. and Kernasovskiy, S. A. and Kovac, J. M. and Kuo, C. L. and Lau, K. and Leitch, E. M. and Lennox, A. and Megerian, K. G. and Minutolo, L. and Moncelsi, L. and Nakato, Y. and Namikawa, T. and Nguyen, H. T. and O’Brient, R. and Ogburn, R. W. and Palladino, S. and Prouve, T. and Pryke, C. and Racine, B. and Reintsema, C. D. and Richter, S. and Schillaci, A. and Schwarz, R. and Schmitt, B. L. and Sheehy, C. D. and Soliman, A. and Germaine, T. St. and Steinbach, B. and Sudiwala, R. V. and Teply, G. P. and Thompson, K. L. and Tolan, J. E. and Tucker, C. and Turner, A. D. and Umiltà, C. and Vergès, C. and Vieregg, A. G. and Wandui, A. and Weber, A. C. and Wiebe, D. V. and Willmert, J. and Wong, C. L. and Wu, W. L. K. and Yang, H. and Yoon, K. W. and Young, E. and Yu, C. and Zeng, L. and Zhang, C. and Zhang, S. (2021) Improved Constraints on Primordial Gravitational Waves using Planck, WMAP, and BICEP/Keck Observations through the 2018 Observing Season. Physical Review Letters, 127 (15). Art. No. 151301. ISSN 0031-9007. doi:10.1103/physrevlett.127.151301.

[img] PDF - Published Version
See Usage Policy.

[img] PDF - Submitted Version
See Usage Policy.

[img] PDF (containing appendices to the main paper) - Supplemental Material
See Usage Policy.


Use this Persistent URL to link to this item:


We present results from an analysis of all data taken by the BICEP2, Keck Array, and BICEP3 CMB polarization experiments up to and including the 2018 observing season. We add additional Keck Array observations at 220 GHz and BICEP3 observations at 95 GHz to the previous 95/150/220  GHz dataset. The Q/U maps now reach depths of 2.8, 2.8, and 8.8  μK_(CMB) arcmin at 95, 150, and 220 GHz, respectively, over an effective area of ≈600 square degrees at 95 GHz and ≈400 square degrees at 150 and 220 GHz. The 220 GHz maps now achieve a signal-to-noise ratio on polarized dust emission exceeding 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 and 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 no longer requires a prior on the frequency spectral index of the dust emission taken from measurements on other regions of the sky. This model is an adequate description of the data at the current noise levels. The likelihood analysis yields the constraint r_(0.05) < 0.036 at 95% confidence. Running maximum likelihood search on simulations we obtain unbiased results and find that σ(r) = 0.009. These are the strongest constraints to date on primordial gravitational waves.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper ItemData and Figures InPhysics : Viewpoint
Ade, P. A. R.0000-0002-5127-0401
Basu Thakur, R.0000-0002-3351-3078
Bock, J. J.0000-0002-5710-5212
Hildebrandt, S. R.0000-0003-0220-0009
Minutolo, L.0000-0002-4876-112X
Moncelsi, L.0000-0002-4242-3015
Schillaci, A.0000-0002-0512-1042
Wandui, A.0000-0002-8232-7343
Zhang, C.0000-0001-8288-5823
Alternate Title:BICEP/Keck XIII: Improved Constraints on Primordial Gravitational Waves using Planck, WMAP, and BICEP/Keck Observations through the 2018 Observing Season
Additional Information:© 2021 American Physical Society. Received 21 June 2021; accepted 12 August 2021; published 4 October 2021. The BICEP/Keck projects have been made possible through a series of grants from the National Science Foundation including Grants No. 0742818, No. 0742592, No. 1044978, No. 1110087, No. 1145172, No. 1145143, No. 1145248, No. 1639040, No. 1638957, No. 1638978, and No. 1638970, and by the Keck Foundation. The development of antenna-coupled detector technology was supported by the JPL Research and Technology Development Fund, and by NASA Grants No. 06-ARPA206-0040, No. 10-SAT10-0017, No. 12-SAT12-0031, No. 14-SAT14-0009, and No. 16-SAT-16-0002. The development and testing of focal planes were supported by the Gordon and Betty Moore Foundation at Caltech. Readout electronics were supported by a Canada Foundation for Innovation grant to UBC. Support for quasioptical filtering was provided by UK STFC Grant No. ST/N000706/1. The computations in this Letter were run on the Odyssey/Cannon cluster supported by the FAS Science Division Research Computing Group at Harvard University. The analysis effort at Stanford and S. L. A. C. is partially supported by the U.S. DOE Office of Science. We thank the staff of the U.S. Antarctic Program and in particular the South Pole Station without whose help this research would not have been possible. Most special thanks go to our heroic winter-overs Robert Schwarz, Steffen Richter, Sam Harrison, Grantland Hall, and Hans Boenish. We thank all those who have contributed past efforts to the BICEP/Keck series of experiments, including the BICEP1 team. We also thank the Planck and WMAP teams for the use of their data, and are grateful to the Planck team for helpful discussions.
Group:Astronomy Department
Funding AgencyGrant Number
W. M. Keck FoundationUNSPECIFIED
JPL Research and Technology Development FundUNSPECIFIED
Gordon and Betty Moore FoundationUNSPECIFIED
Canada Foundation for InnovationUNSPECIFIED
Science and Technology Facilities Council (STFC)ST/N000706/1
Harvard UniversityUNSPECIFIED
Department of Energy (DOE)UNSPECIFIED
Issue or Number:15
Record Number:CaltechAUTHORS:20211004-183512532
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:111176
Deposited By: Tony Diaz
Deposited On:04 Oct 2021 19:03
Last Modified:04 Oct 2021 19:03

Repository Staff Only: item control page