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Constraints on Cosmology from the Cosmic Microwave Background Power Spectrum of the 2500 deg^2 SPT-SZ Survey

Hou, Z. and de Putter, R. and Padin, S. (2014) Constraints on Cosmology from the Cosmic Microwave Background Power Spectrum of the 2500 deg^2 SPT-SZ Survey. Astrophysical Journal, 782 (2). Art. No. 74. ISSN 0004-637X.

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We explore extensions to the ΛCDM cosmology using measurements of the cosmic microwave background (CMB) from the recent SPT-SZ survey, along with data from WMAP7 and measurements of H_0 and baryon acoustic oscillation (BAO). We check for consistency within ΛCDM between these data sets, and find some tension. The CMB alone gives weak support to physics beyond ΛCDM, due to a slight trend relative to ΛCDM of decreasing power toward smaller angular scales. While it may be due to statistical fluctuation, this trend could also be explained by several extensions. We consider running of the primordial spectral index (dn_s /d ln k), as well as two extensions that modify the damping tail power (the primordial helium abundance Y_p and the effective number of neutrino species N_(eff)) and one that modifies the large-scale power due to the integrated Sachs-Wolfe effect (the sum of neutrino masses ∑m_ν). These extensions have similar observational consequences and are partially degenerate when considered simultaneously. Of the six one-parameter extensions considered, we find CMB to have the largest preference for dn_s/d ln k with –0.046 < dns/d ln k < –0.003 at 95% confidence, which strengthens to a 2.7σ indication of dn_s/d ln k < 0 from CMB+BAO+H_0. Detectable dn_s/d ln k ≠ 0 is difficult to explain in the context of single-field, slow-roll inflation models. We find N_(eff) = 3.62 ± 0.48 for the CMB, which tightens to N(eff) = 3.71 ± 0.35 from CMB+BAO+H_0. Larger values of N_(eff) relieve the mild tension between CMB, BAO, and H_0. When the Sunyaev-Zel'dovich selected galaxy cluster abundances (SPT_(CL)) data are also included, we obtain N_(eff) = 3.29 ± 0.31. Allowing for ∑m_ν gives a 3.0σ detection of ∑m_ν > 0 from CMB+BAO+H_0 + SPT_(CL). The median value is (0.32 ± 0.11) eV, a factor of six above the lower bound set by neutrino oscillation observations. All data sets except H_0 show some preference for massive neutrinos; data combinations including H_0 favor nonzero masses only if BAO data are also included. We also constrain the two-parameter extensions N_(eff) + ∑m_ν and N_(eff) + Y_p to explore constraints on additional light species and big bang nucleosynthesis, respectively.

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Alternate Title:Constraints on Cosmology from the Cosmic Microwave Background Power Spectrum of the 2500-square degree SPT-SZ Survey
Additional Information:© 2014 American Astronomical Society. Received 2012 December 26; accepted 2013 November 12; published 2014 January 29. 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. 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. This research used resources of the National Energy Research Scientific Computing Center (NERSC), 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. 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.
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 (CIAR)UNSPECIFIED
Alfred P. Sloan FoundationUNSPECIFIED
Department of Energy (DOE)DE-AC02-05CH11231
Open Science GridUNSPECIFIED
NSFPHY 1148698
Subject Keywords:cosmic background radiation; cosmological parameters; early universe; inflation
Record Number:CaltechAUTHORS:20140519-094821926
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Official Citation:Constraints on Cosmology from the Cosmic Microwave Background Power Spectrum of the 2500 deg2 SPT-SZ Survey Z. Hou et al. 2014 ApJ 782 74
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:45816
Deposited By: Ruth Sustaita
Deposited On:19 May 2014 17:31
Last Modified:06 Jan 2016 17:52

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