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A Measurement of the Cosmic Microwave Background Damping Tail from the 2500-Square-Degree SPT-SZ Survey

Story, K. T. and Lueker, M. and Padin, S. and Vieira, J. D. (2013) A Measurement of the Cosmic Microwave Background Damping Tail from the 2500-Square-Degree SPT-SZ Survey. Astrophysical Journal, 779 (1). Art. No. 86. ISSN 0004-637X.

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We present a measurement of the cosmic microwave background (CMB) temperature power spectrum using data from the recently completed South Pole Telescope Sunyaev-Zel'dovich (SPT-SZ) survey. This measurement is made from observations of 2540 deg^2 of sky with arcminute resolution at 150 GHz, and improves upon previous measurements using the SPT by tripling the sky area. We report CMB temperature anisotropy power over the multipole range 650 < ℓ < 3000. We fit the SPT bandpowers, combined with the 7 yr Wilkinson Microwave Anisotropy Probe (WMAP7) data, with a six-parameter ΛCDM cosmological model and find that the two datasets are consistent and well fit by the model. Adding SPT measurements significantly improves ΛCDM parameter constraints; in particular, the constraint on θ_s tightens by a factor of 2.7. The impact of gravitational lensing is detected at 8.1σ, the most significant detection to date. This sensitivity of the SPT+WMAP7 data to lensing by large-scale structure at low redshifts allows us to constrain the mean curvature of the observable universe with CMB data alone to be Ω_k=-0.003^(+0.014)_(-0.018). Using the SPT+WMAP7 data, we measure the spectral index of scalar fluctuations to be n_s = 0.9623 ± 0.0097 in the ΛCDM model, a 3.9σ preference for a scale-dependent spectrum with n_s < 1. The SPT measurement of the CMB damping tail helps break the degeneracy that exists between the tensor-to-scalar ratio r and n_s in large-scale CMB measurements, leading to an upper limit of r < 0.18 (95% C.L.) in the ΛCDM+r model. Adding low-redshift measurements of the Hubble constant (H_0) and the baryon acoustic oscillation (BAO) feature to the SPT+WMAP7 data leads to further improvements. The combination of SPT+WMAP7+H_0+BAO constrains n_s = 0.9538 ± 0.0081 in the ΛCDM model, a 5.7σ detection of n_s < 1, and places an upper limit of r < 0.11 (95% C.L.) in the ΛCDM+r model. These new constraints on n_s and r have significant implications for our understanding of inflation, which we discuss in the context of selected single-field inflation models.

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Additional Information:© 2013 American Astronomical Society. Received 2012 October 25; accepted 2013 October 9; published 2013 November 26. We thank Scott Dodelson, John Peacock, David Baumann, and Antonio Riotto for useful conversations. The SPT is supported by the National Science Foundation through grant ANT-0638937, with partial support provided by NSF grant PHY-1125897, the Kavli Foundation, and the Gordon and Betty Moore Foundation. The McGill group acknowledges funding from the National Sciences and Engineering Research Council of Canada, Canada Research Chairs program, and the Canadian Institute for Advanced Research. Work at Harvard is supported by grant AST-1009012. R. Keisler acknowledges support from NASA Hubble Fellowship grant HF-51275.01, B. A. Benson a KICP Fellowship, M. Dobbs an Alfred P. Sloan Research Fellowship, O. Zahn a BCCP fellowship, M. Millea and L. Knox a NSF grant 0709498. This research used resources of the National Energy Research Scientific Computing Center, which is supported by the Office of Science of the U.S. Department of Energy under contract No. DE-AC02-05CH11231, and the resources of the University of Chicago Computing Cooperative (UC3), supported in part by the Open Science Grid, NSF grant NSF PHY 1148698. Some of the results in this paper have been derived using the HEALPix (Gόrski et al. 2005) package. We acknowledge the use of the Legacy Archive for Microwave Background Data Analysis (LAMBDA). Support for LAMBDA is provided by the NASA Office of Space Science. Facility: South Pole Telescope
Funding AgencyGrant Number
Kavli FoundationUNSPECIFIED
Gordon and Betty Moore FoundationUNSPECIFIED
Natural Sciences and Engineering Research Council of Canada (NSERC)UNSPECIFIED
Canada Research Chairs ProgramUNSPECIFIED
Canadian Institute for Advanced Research (CIFAR)UNSPECIFIED
NASA Hubble FellowshipHF-51275.01
Kavli Institute for Cosmological PhysicsUNSPECIFIED
Alfred P. Sloan FoundationUNSPECIFIED
Department of Energy (DOE) Office of ScienceDE-AC02-05CH11231
Open Science GridUNSPECIFIED
Subject Keywords:cosmic background radiation; cosmology: observations; large-scale structure of universe
Issue or Number:1
Record Number:CaltechAUTHORS:20140121-082425604
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Official Citation:A Measurement of the Cosmic Microwave Background Damping Tail from the 2500-Square-Degree SPT-SZ Survey K. T. Story et al. 2013 ApJ 779 86
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:43443
Deposited By: Ruth Sustaita
Deposited On:22 Jan 2014 16:24
Last Modified:03 Oct 2019 06:07

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