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Gravitational-Wave Cosmology across 29 Decades in Frequency

Lasky, Paul D. and Mingarelli, Chiara M. F. and Smith, Tristan L. and Giblin, John T., Jr. and Thrane, Eric and Reardon, Daniel J. and Caldwell, Robert and Bailes, Matthew and Bhat, N. D. Ramesh and Burke-Spolaor, Sarah and Dai, Shi and Dempsey, James and Hobbs, George and Kerr, Matthew and Levin, Yuri and Manchester, Richard N. and Osłowski, Stefan and Ravi, Vikram and Rosado, Pablo A. and Shannon, Ryan M. and Spiewak, Renée and van Straten, Willem and Toomey, Lawrence and Wang, Jingbo and Wen, Linqing and You, Xiaopeng and Zhu, Xingjiang (2016) Gravitational-Wave Cosmology across 29 Decades in Frequency. Physical Review X, 6 (1). Art. No. 011035. ISSN 2160-3308. doi:10.1103/PhysRevX.6.011035.

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Quantum fluctuations of the gravitational field in the early Universe, amplified by inflation, produce a primordial gravitational-wave background across a broad frequency band. We derive constraints on the spectrum of this gravitational radiation, and hence on theories of the early Universe, by combining experiments that cover 29 orders of magnitude in frequency. These include Planck observations of cosmic microwave background temperature and polarization power spectra and lensing, together with baryon acoustic oscillations and big bang nucleosynthesis measurements, as well as new pulsar timing array and ground-based interferometer limits. While individual experiments constrain the gravitational-wave energy density in specific frequency bands, the combination of experiments allows us to constrain cosmological parameters, including the inflationary spectral index n_t and the tensor-to-scalar ratio r. Results from individual experiments include the most stringent nanohertz limit of the primordial background to date from the Parkes Pulsar Timing Array, Ω_(GW)(f) < 2.3 × 10^(−10). Observations of the cosmic microwave background alone limit the gravitational-wave spectral index at 95% confidence to n_t ≲ 5 for a tensor-to-scalar ratio of r = 0.11. However, the combination of all the above experiments limits n_t < 0.36. Future Advanced LIGO observations are expected to further constrain n_t < 0.34 by 2020. When cosmic microwave background experiments detect a nonzero r, our results will imply even more stringent constraints on n_t and, hence, theories of the early Universe.

Item Type:Article
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URLURL TypeDescription Paper InPhysics : Synopsis
Lasky, Paul D.0000-0003-3763-1386
Mingarelli, Chiara M. F.0000-0002-4307-1322
Thrane, Eric0000-0002-4418-3895
Bailes, Matthew0000-0003-3294-3081
Burke-Spolaor, Sarah0000-0003-4052-7838
Dai, Shi0000-0002-9618-2499
Hobbs, George0000-0003-1502-100X
Ravi, Vikram0000-0002-7252-5485
Wang, Jingbo0000-0001-9782-1603
Additional Information:© 2016 The Authors. Published by the American Physical Society. This article is available under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. (Received 13 October 2015; revised manuscript received 8 January 2016; published 31 March 2016) P. D. L. is grateful to Justin Ellis for valuable support with the pulsar timing package pal2. We are extremely grateful to the three referees who all provided excellent feedback that improved the manuscript. This work was initiated at the Aspen Center for Physics, which is supported by National Science Foundation Grant No. PHY-1066293. J. T. G. is supported by the National Science Foundation, PHY-1414479. C. M. F. M. was supported by a Marie Curie International Outgoing Fellowship within the European Union Seventh Framework Programme. R. C. is supported in part by DOE Grant No. DE-SC0010386. The Parkes radio telescope is part of the Australia Telescope National Facility, which is funded by the Commonwealth of Australia for operation as a National Facility managed by CSIRO. Y. L. and G. H. are recipients of ARC Future Fellowships (respectively, FT110100384 and FT120100595). Y. L., M. B., W. v. S., P. A. R., and P. D. L. are supported by ARC Discovery Project No. DP140102578. S. O. is supported by the Alexander von Humboldt Foundation. L. W. and X. Z. acknowledge support from the ARC. J. W. is supported by NSFC Project No. 11403086 and West Light Foundation of CAS XBBS201322. X. Y. is supported by NSFC Project No. U1231120, FRFCU Project No. XDJK2015B012, and China Scholarship Council (CSC). E. T. is supported by ARC Future Fellowship FT150100281.
Funding AgencyGrant Number
Marie Curie FellowshipUNSPECIFIED
Department of Energy (DOE)DE-SC0010386
Commonwealth of AustraliaUNSPECIFIED
Australian Research CouncilFT110100384
Australian Research CouncilFT120100595
Australian Research CouncilDP140102578
Alexander von Humboldt FoundationUNSPECIFIED
National Natural Science Foundation of China11403086
CAS West Light FoundationXBBS201322
National Natural Science Foundation of ChinaU1231120
Fundamental Research Funds for the Central Universities (FRFCU)XDJK2015B012
China Scholarship CouncilUNSPECIFIED
Australian Research CouncilFT150100281
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Space Radiation Laboratory2016-26
Issue or Number:1
Record Number:CaltechAUTHORS:20160420-161703352
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Official Citation:Gravitational-Wave Cosmology across 29 Decades in Frequency Paul D. Lasky et al. Phys. Rev. X 6, 011035 – Published 31 March 2016
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:66341
Deposited By: George Porter
Deposited On:21 Apr 2016 14:31
Last Modified:10 Nov 2021 23:56

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