A measurement of the secondary-CMB and millimeter-wave-foreground bispectrum using 800 deg{sup 2} of south pole telescope data

Journal Article · Tue Apr 01 00:00:00 EDT 2014 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/784/2/143· OSTI ID:22357264

Crawford, T. M.; Schaffer, K. K.; Bhattacharya, S.; Benson, B. A.; Bleem, L. E.; Carlstrom, J. E.; Chang, C. L.; Crites, A. T.; Hoover, S. ^[1]; Aird, K. A.; Hrubes, J. D. ^[2]; Cho, H-M. ^[3]; De Haan, T.; Dobbs, M. A.; Dudley, J.; Holder, G. P. ^[4]; George, E. M.; Holzapfel, W. L. ^[5]; Halverson, N. W. ^[6]; others, and

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1. Kavli Institute for Cosmological Physics, University of Chicago, Chicago, IL 60637 (United States)
2. University of Chicago, Chicago, IL 60637 (United States)
3. NIST Quantum Devices Group, Boulder, CO 80305 (United States)
4. Department of Physics, McGill University, Montreal, Quebec H3A 2T8 (Canada)
5. Department of Physics, University of California, Berkeley, CA 94720 (United States)
6. Department of Astrophysical and Planetary Sciences and Department of Physics, University of Colorado, Boulder, CO 80309 (United States)

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{sup 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{sub 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 {sub kSZ} = 2.9 ± 1.6 μK{sup 2}, or A {sub kSZ} = 2.6 ± 1.8 μK{sup 2} if the default A {sub kSZ} > 0 prior is removed.

• OSTI ID: 22357264
• Journal Information: Astrophysical Journal, Vol. 784, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
AMPLITUDES
BACKGROUND RADIATION
COMPARATIVE EVALUATIONS
COSMOLOGY
DATA ANALYSIS
DETECTION
EMISSION
FORECASTING
GALAXIES
GALAXY NUCLEI
GHZ RANGE
LIMITING VALUES
SPECTRA
STARS
TELESCOPES