Planck 2013 results. XXV. Searches for cosmic strings and other topological defects

Jussi Varis, Jussi Tuovinen, Adam Moss (Corresponding Author), Planck Collaboration

    Research output: Contribution to journalArticleScientificpeer-review

    103 Citations (Scopus)

    Abstract

    Planck data have been used to provide stringent new constraints on cosmic strings and other defects. We describe forecasts of the CMB power spectrum induced by cosmic strings, calculating these from network models and simulations using line-of-sight Boltzmann solvers. We have studied Nambu-Goto cosmic strings, as well as field theory strings for which radiative effects are important, thus spanning the range of theoretical uncertainty in the underlying strings models. We have added the angular power spectrum from strings to that for a simple adiabatic model, with the extra fraction defined as f10 at multipole l = 10. This parameter has been added to the standard six parameter fit using COSMOMC with flat priors. For the Nambu-Goto string model, we have obtained a constraint on the string tension of Gµ/c2 <1.5 * 10-7 and f10 <0.015 at 95% confidence that can be improved to Gµ/c2 <1.3 * 10-7 and f10 <0.010 on inclusion of high-l CMB data. For the Abelian-Higgs field theory model we find, GµAH/c2<3.2 * 10-7 and f10 <0.028. The marginalised likelihoods for f10 and in the f10-Obh2 plane are also presented. We have additionally obtained comparable constraints on f10 for models with semilocal strings and global textures. In terms of the effective defect energy scale these are somewhat weaker at Gµ/c2 < 1.1 * 10-6. We have made complementarity searches for the specific non-Gaussian signatures of cosmic strings, calibrating with all-sky Planck resolution CMB maps generated from networks of post-recombination strings. We have validated our non-Gaussian searches using these simulated maps in a Planck-realistic context, estimating sensitivities of up to ?Gµ/c2 ~ 4 * 10-7. We have obtained upper limits on the string tension at 95% confidence of Gµ/c2 <9.0 * 10-7 with modal bispectrum estimation and Gµ/c2 <7.8 * 10-7 for real space searches with Minkowski functionals. These are conservative upper bounds because only post-recombination string contributions have been included in the non-Gaussian analysis.
    Original languageEnglish
    Article numberA25
    Number of pages21
    JournalAstronomy and Astrophysics
    Volume571
    DOIs
    Publication statusPublished - 2014
    MoE publication typeA1 Journal article-refereed

    Fingerprint

    defect
    strings
    defects
    recombination
    complementarity
    power spectra
    confidence
    texture
    calibrating
    functionals
    string theory
    forecasting
    line of sight
    multipoles
    simulation
    energy
    sky
    estimating
    textures
    signatures

    Keywords

    • cosmic background radiation
    • cosmological parameters
    • early Universe
    • large-scale structure of Universe
    • cosmology

    Cite this

    Varis, Jussi ; Tuovinen, Jussi ; Moss, Adam ; Planck Collaboration. / Planck 2013 results. XXV. Searches for cosmic strings and other topological defects. In: Astronomy and Astrophysics. 2014 ; Vol. 571.
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    abstract = "Planck data have been used to provide stringent new constraints on cosmic strings and other defects. We describe forecasts of the CMB power spectrum induced by cosmic strings, calculating these from network models and simulations using line-of-sight Boltzmann solvers. We have studied Nambu-Goto cosmic strings, as well as field theory strings for which radiative effects are important, thus spanning the range of theoretical uncertainty in the underlying strings models. We have added the angular power spectrum from strings to that for a simple adiabatic model, with the extra fraction defined as f10 at multipole l = 10. This parameter has been added to the standard six parameter fit using COSMOMC with flat priors. For the Nambu-Goto string model, we have obtained a constraint on the string tension of Gµ/c2 <1.5 * 10-7 and f10 <0.015 at 95{\%} confidence that can be improved to Gµ/c2 <1.3 * 10-7 and f10 <0.010 on inclusion of high-l CMB data. For the Abelian-Higgs field theory model we find, GµAH/c2<3.2 * 10-7 and f10 <0.028. The marginalised likelihoods for f10 and in the f10-Obh2 plane are also presented. We have additionally obtained comparable constraints on f10 for models with semilocal strings and global textures. In terms of the effective defect energy scale these are somewhat weaker at Gµ/c2 < 1.1 * 10-6. We have made complementarity searches for the specific non-Gaussian signatures of cosmic strings, calibrating with all-sky Planck resolution CMB maps generated from networks of post-recombination strings. We have validated our non-Gaussian searches using these simulated maps in a Planck-realistic context, estimating sensitivities of up to ?Gµ/c2 ~ 4 * 10-7. We have obtained upper limits on the string tension at 95{\%} confidence of Gµ/c2 <9.0 * 10-7 with modal bispectrum estimation and Gµ/c2 <7.8 * 10-7 for real space searches with Minkowski functionals. These are conservative upper bounds because only post-recombination string contributions have been included in the non-Gaussian analysis.",
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    Planck 2013 results. XXV. Searches for cosmic strings and other topological defects. / Varis, Jussi; Tuovinen, Jussi; Moss, Adam (Corresponding Author); Planck Collaboration.

    In: Astronomy and Astrophysics, Vol. 571, A25, 2014.

    Research output: Contribution to journalArticleScientificpeer-review

    TY - JOUR

    T1 - Planck 2013 results. XXV. Searches for cosmic strings and other topological defects

    AU - Varis, Jussi

    AU - Tuovinen, Jussi

    AU - Moss, Adam

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    N2 - Planck data have been used to provide stringent new constraints on cosmic strings and other defects. We describe forecasts of the CMB power spectrum induced by cosmic strings, calculating these from network models and simulations using line-of-sight Boltzmann solvers. We have studied Nambu-Goto cosmic strings, as well as field theory strings for which radiative effects are important, thus spanning the range of theoretical uncertainty in the underlying strings models. We have added the angular power spectrum from strings to that for a simple adiabatic model, with the extra fraction defined as f10 at multipole l = 10. This parameter has been added to the standard six parameter fit using COSMOMC with flat priors. For the Nambu-Goto string model, we have obtained a constraint on the string tension of Gµ/c2 <1.5 * 10-7 and f10 <0.015 at 95% confidence that can be improved to Gµ/c2 <1.3 * 10-7 and f10 <0.010 on inclusion of high-l CMB data. For the Abelian-Higgs field theory model we find, GµAH/c2<3.2 * 10-7 and f10 <0.028. The marginalised likelihoods for f10 and in the f10-Obh2 plane are also presented. We have additionally obtained comparable constraints on f10 for models with semilocal strings and global textures. In terms of the effective defect energy scale these are somewhat weaker at Gµ/c2 < 1.1 * 10-6. We have made complementarity searches for the specific non-Gaussian signatures of cosmic strings, calibrating with all-sky Planck resolution CMB maps generated from networks of post-recombination strings. We have validated our non-Gaussian searches using these simulated maps in a Planck-realistic context, estimating sensitivities of up to ?Gµ/c2 ~ 4 * 10-7. We have obtained upper limits on the string tension at 95% confidence of Gµ/c2 <9.0 * 10-7 with modal bispectrum estimation and Gµ/c2 <7.8 * 10-7 for real space searches with Minkowski functionals. These are conservative upper bounds because only post-recombination string contributions have been included in the non-Gaussian analysis.

    AB - Planck data have been used to provide stringent new constraints on cosmic strings and other defects. We describe forecasts of the CMB power spectrum induced by cosmic strings, calculating these from network models and simulations using line-of-sight Boltzmann solvers. We have studied Nambu-Goto cosmic strings, as well as field theory strings for which radiative effects are important, thus spanning the range of theoretical uncertainty in the underlying strings models. We have added the angular power spectrum from strings to that for a simple adiabatic model, with the extra fraction defined as f10 at multipole l = 10. This parameter has been added to the standard six parameter fit using COSMOMC with flat priors. For the Nambu-Goto string model, we have obtained a constraint on the string tension of Gµ/c2 <1.5 * 10-7 and f10 <0.015 at 95% confidence that can be improved to Gµ/c2 <1.3 * 10-7 and f10 <0.010 on inclusion of high-l CMB data. For the Abelian-Higgs field theory model we find, GµAH/c2<3.2 * 10-7 and f10 <0.028. The marginalised likelihoods for f10 and in the f10-Obh2 plane are also presented. We have additionally obtained comparable constraints on f10 for models with semilocal strings and global textures. In terms of the effective defect energy scale these are somewhat weaker at Gµ/c2 < 1.1 * 10-6. We have made complementarity searches for the specific non-Gaussian signatures of cosmic strings, calibrating with all-sky Planck resolution CMB maps generated from networks of post-recombination strings. We have validated our non-Gaussian searches using these simulated maps in a Planck-realistic context, estimating sensitivities of up to ?Gµ/c2 ~ 4 * 10-7. We have obtained upper limits on the string tension at 95% confidence of Gµ/c2 <9.0 * 10-7 with modal bispectrum estimation and Gµ/c2 <7.8 * 10-7 for real space searches with Minkowski functionals. These are conservative upper bounds because only post-recombination string contributions have been included in the non-Gaussian analysis.

    KW - cosmic background radiation

    KW - cosmological parameters

    KW - early Universe

    KW - large-scale structure of Universe

    KW - cosmology

    U2 - 10.1051/0004-6361/201321621

    DO - 10.1051/0004-6361/201321621

    M3 - Article

    VL - 571

    JO - Astronomy and Astrophysics

    JF - Astronomy and Astrophysics

    SN - 0004-6361

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