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A Measurement of the Secondary-CMB and Millimeter-wave-foreground Bispectrum using 800 deg^2 of South Pole Telescope Data

Crawford, T. M. and Lueker, M. and Padin, S. and Vieira, J. D. (2014) A Measurement of the Secondary-CMB and Millimeter-wave-foreground Bispectrum using 800 deg^2 of South Pole Telescope Data. Astrophysical Journal, 784 (2). Art. No. 143. ISSN 0004-637X.

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We present a measurement of the angular bispectrum of the millimeter-wave sky in observing bands centered at roughly 95, 150, and 220 GHz, on angular scales of 1'≾θ≾10' (multipole number 1000≾l≾10,000). At these frequencies and angular scales, the main contributions to the bispectrum are expected to be the thermal Sunyaev-Zel'dovich (tSZ) effect and emission from extragalactic sources, predominantly dusty, star-forming galaxies (DSFGs) and active galactic nuclei. We measure the bispectrum in 800 deg^2 of three-band South Pole Telescope data, and we use a multi-frequency fitting procedure to separate the bispectrum of the tSZ effect from the extragalactic source contribution. We simultaneously detect the bispectrum of the tSZ effect at >10σ, the unclustered component of the extragalactic source bispectrum at >5σ in each frequency band, and the bispectrum due to the clustering of DSFGs—i.e., the clustered cosmic infrared background (CIB) bispectrum—at >5σ. This is the first reported detection of the clustered CIB bispectrum. We use the measured tSZ bispectrum amplitude, compared to model predictions, to constrain the normalization of the matter power spectrum to be σ_8 = 0.787 ± 0.031 and to predict the amplitude of the tSZ power spectrum at l = 3000. This prediction improves our ability to separate the thermal and kinematic contributions to the total SZ power spectrum. The addition of bispectrum data improves our constraint on the tSZ power spectrum amplitude by a factor of two compared to power spectrum measurements alone and demonstrates a preference for a nonzero kinematic SZ (kSZ) power spectrum, with a derived constraint on the kSZ amplitude at l = 3000 of A_(kSZ) = 2.9 ± 1.6 μK^2, or A_(kSZ) = 2.6 ± 1.8 μK^2 if the default A_(kSZ) > 0 prior is removed.

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Additional Information:© 2014 American Astronomical Society. Received 2013 March 13; accepted 2014 February 24; published 2014 March 14. We thank Blake Sherwin for providing the ACT l-space filter function, and we thank an anonymous referee for helpful comments. T. Crawford and R. Keisler thank the University of Texas Department of Astronomy and the Texas Cosmology Center, where much of this work was done, for their hospitality. 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. S. Bhattacharya acknowledges support from NSF grant AST-1009811, R. Keisler from NASA Hubble Fellowship grant HF-51275.01, B. Benson from a KICP Fellowship, M. Dobbs from an Alfred P. Sloan Research Fellowship, O. Zahn from a BCCP fellowship, and L. Knox and M. Millea from NSF grant 0709498. Some of the results in this paper have been derived using the HEALPix (Gόrski et al. 2005) package. 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 resources of the University of Chicago Computing Cooperative (UC3), supported in part by the Open Science Grid, NSF grant 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 (CIFAR)UNSPECIFIED
Kavli Institute for Cosmological PhysicsUNSPECIFIED
Alfred P. Sloan FoundationUNSPECIFIED
Department of Energy (DOE)DE-AC02-05CH11231
Open Science GridUNSPECIFIED
Subject Keywords:cosmic background radiation; cosmology: observations; methods: data analysis
Issue or Number:2
Record Number:CaltechAUTHORS:20140606-113330005
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Official Citation:A Measurement of the Secondary-CMB and Millimeter-wave-foreground Bispectrum using 800 deg2 of South Pole Telescope Data T. M. Crawford et al. 2014 ApJ 784 143
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:46126
Deposited By: Ruth Sustaita
Deposited On:06 Jun 2014 19:20
Last Modified:03 Oct 2019 06:41

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