Planck 2013 results: XXIV. Constraints on primordial non-Gaussianity

Jussi Varis, Jussi Tuovinen, Planck Collaboration

    Research output: Contribution to journalArticleScientificpeer-review

    206 Citations (Scopus)

    Abstract

    The Planck nominal mission cosmic microwave background (CMB) maps yield unprecedented constraints on primordial non-Gaussianity (NG). Using three optimal bispectrum estimators, separable template-fitting (KSW), binned, and modal, we obtain consistent values for the primordial local, equilateral, and orthogonal bispectrum amplitudes, quoting as our final result fNLlocal = 2.7 ± 5.8, fNLequil = -42 ± 75, and fNLorth = -25 ± 39 (68% CL statistical). Non-Gaussianity is detected in the data; using skew-C\sub{\ell} statistics we find a nonzero bispectrum from residual point sources, and the integrated-Sachs-Wolfe-lensing bispectrum at a level expected in the {\wedge}CDM scenario. The results are based on comprehensive cross-validation of these estimators on Gaussian and non-Gaussian simulations, are stable across component separation techniques, pass an extensive suite of tests, and are confirmed by skew-Cl, wavelet bispectrum and Minkowski functional estimators. Beyond estimates of individual shape amplitudes, we present model-independent, three-dimensional reconstructions of the Planck CMB bispectrum and thus derive constraints on early-Universe scenarios that generate primordial NG, including general single-field models of inflation, excited initial states (non-Bunch-Davies vacua), and directionally-dependent vector models. We provide an initial survey of scale-dependent feature and resonance models. These results bound both general single-field and multi-field model parameter ranges, such as the speed of sound, cs = 0.02 (95% CL), in an effective field theory parametrization, and the curvaton decay fraction rD = 0.15 (95% CL). The Planck data significantly limit the viable parameter space of the ekpyrotic/cyclic scenarios. The amplitude of the four-point function in the local model tNL<2800 (95% CL). Taken together, these constraints represent the highest precision tests to date of physical mechanisms for the origin of cosmic structure.
    Original languageEnglish
    Article numberA24
    Number of pages58
    JournalAstronomy and Astrophysics
    Volume571
    DOIs
    Publication statusPublished - 2014
    MoE publication typeA1 Journal article-refereed

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    microwaves
    inflation
    wedges
    point sources
    wavelet
    point source
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    universe
    statistics
    acoustics
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    Keywords

    • cosmic background radiation
    • cosmology
    • early Universe
    • inflation
    • data analysis

    Cite this

    @article{f7b6192b2d9a4e24a5145101f4c073e1,
    title = "Planck 2013 results: XXIV. Constraints on primordial non-Gaussianity",
    abstract = "The Planck nominal mission cosmic microwave background (CMB) maps yield unprecedented constraints on primordial non-Gaussianity (NG). Using three optimal bispectrum estimators, separable template-fitting (KSW), binned, and modal, we obtain consistent values for the primordial local, equilateral, and orthogonal bispectrum amplitudes, quoting as our final result fNLlocal = 2.7 ± 5.8, fNLequil = -42 ± 75, and fNLorth = -25 ± 39 (68{\%} CL statistical). Non-Gaussianity is detected in the data; using skew-C\sub{\ell} statistics we find a nonzero bispectrum from residual point sources, and the integrated-Sachs-Wolfe-lensing bispectrum at a level expected in the {\wedge}CDM scenario. The results are based on comprehensive cross-validation of these estimators on Gaussian and non-Gaussian simulations, are stable across component separation techniques, pass an extensive suite of tests, and are confirmed by skew-Cl, wavelet bispectrum and Minkowski functional estimators. Beyond estimates of individual shape amplitudes, we present model-independent, three-dimensional reconstructions of the Planck CMB bispectrum and thus derive constraints on early-Universe scenarios that generate primordial NG, including general single-field models of inflation, excited initial states (non-Bunch-Davies vacua), and directionally-dependent vector models. We provide an initial survey of scale-dependent feature and resonance models. These results bound both general single-field and multi-field model parameter ranges, such as the speed of sound, cs = 0.02 (95{\%} CL), in an effective field theory parametrization, and the curvaton decay fraction rD = 0.15 (95{\%} CL). The Planck data significantly limit the viable parameter space of the ekpyrotic/cyclic scenarios. The amplitude of the four-point function in the local model tNL<2800 (95{\%} CL). Taken together, these constraints represent the highest precision tests to date of physical mechanisms for the origin of cosmic structure.",
    keywords = "cosmic background radiation, cosmology, early Universe, inflation, data analysis",
    author = "Jussi Varis and Jussi Tuovinen and {Planck Collaboration}",
    note = "Project code: 18080",
    year = "2014",
    doi = "10.1051/0004-6361/201321554",
    language = "English",
    volume = "571",
    journal = "Astronomy and Astrophysics",
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    }

    Planck 2013 results : XXIV. Constraints on primordial non-Gaussianity. / Varis, Jussi; Tuovinen, Jussi; Planck Collaboration.

    In: Astronomy and Astrophysics, Vol. 571, A24, 2014.

    Research output: Contribution to journalArticleScientificpeer-review

    TY - JOUR

    T1 - Planck 2013 results

    T2 - XXIV. Constraints on primordial non-Gaussianity

    AU - Varis, Jussi

    AU - Tuovinen, Jussi

    AU - Planck Collaboration

    N1 - Project code: 18080

    PY - 2014

    Y1 - 2014

    N2 - The Planck nominal mission cosmic microwave background (CMB) maps yield unprecedented constraints on primordial non-Gaussianity (NG). Using three optimal bispectrum estimators, separable template-fitting (KSW), binned, and modal, we obtain consistent values for the primordial local, equilateral, and orthogonal bispectrum amplitudes, quoting as our final result fNLlocal = 2.7 ± 5.8, fNLequil = -42 ± 75, and fNLorth = -25 ± 39 (68% CL statistical). Non-Gaussianity is detected in the data; using skew-C\sub{\ell} statistics we find a nonzero bispectrum from residual point sources, and the integrated-Sachs-Wolfe-lensing bispectrum at a level expected in the {\wedge}CDM scenario. The results are based on comprehensive cross-validation of these estimators on Gaussian and non-Gaussian simulations, are stable across component separation techniques, pass an extensive suite of tests, and are confirmed by skew-Cl, wavelet bispectrum and Minkowski functional estimators. Beyond estimates of individual shape amplitudes, we present model-independent, three-dimensional reconstructions of the Planck CMB bispectrum and thus derive constraints on early-Universe scenarios that generate primordial NG, including general single-field models of inflation, excited initial states (non-Bunch-Davies vacua), and directionally-dependent vector models. We provide an initial survey of scale-dependent feature and resonance models. These results bound both general single-field and multi-field model parameter ranges, such as the speed of sound, cs = 0.02 (95% CL), in an effective field theory parametrization, and the curvaton decay fraction rD = 0.15 (95% CL). The Planck data significantly limit the viable parameter space of the ekpyrotic/cyclic scenarios. The amplitude of the four-point function in the local model tNL<2800 (95% CL). Taken together, these constraints represent the highest precision tests to date of physical mechanisms for the origin of cosmic structure.

    AB - The Planck nominal mission cosmic microwave background (CMB) maps yield unprecedented constraints on primordial non-Gaussianity (NG). Using three optimal bispectrum estimators, separable template-fitting (KSW), binned, and modal, we obtain consistent values for the primordial local, equilateral, and orthogonal bispectrum amplitudes, quoting as our final result fNLlocal = 2.7 ± 5.8, fNLequil = -42 ± 75, and fNLorth = -25 ± 39 (68% CL statistical). Non-Gaussianity is detected in the data; using skew-C\sub{\ell} statistics we find a nonzero bispectrum from residual point sources, and the integrated-Sachs-Wolfe-lensing bispectrum at a level expected in the {\wedge}CDM scenario. The results are based on comprehensive cross-validation of these estimators on Gaussian and non-Gaussian simulations, are stable across component separation techniques, pass an extensive suite of tests, and are confirmed by skew-Cl, wavelet bispectrum and Minkowski functional estimators. Beyond estimates of individual shape amplitudes, we present model-independent, three-dimensional reconstructions of the Planck CMB bispectrum and thus derive constraints on early-Universe scenarios that generate primordial NG, including general single-field models of inflation, excited initial states (non-Bunch-Davies vacua), and directionally-dependent vector models. We provide an initial survey of scale-dependent feature and resonance models. These results bound both general single-field and multi-field model parameter ranges, such as the speed of sound, cs = 0.02 (95% CL), in an effective field theory parametrization, and the curvaton decay fraction rD = 0.15 (95% CL). The Planck data significantly limit the viable parameter space of the ekpyrotic/cyclic scenarios. The amplitude of the four-point function in the local model tNL<2800 (95% CL). Taken together, these constraints represent the highest precision tests to date of physical mechanisms for the origin of cosmic structure.

    KW - cosmic background radiation

    KW - cosmology

    KW - early Universe

    KW - inflation

    KW - data analysis

    U2 - 10.1051/0004-6361/201321554

    DO - 10.1051/0004-6361/201321554

    M3 - Article

    VL - 571

    JO - Astronomy and Astrophysics

    JF - Astronomy and Astrophysics

    SN - 0004-6361

    M1 - A24

    ER -