### Abstract

Original language | English |
---|---|

Article number | A25 |

Number of pages | 21 |

Journal | Astronomy and Astrophysics |

Volume | 571 |

DOIs | |

Publication status | Published - 2014 |

MoE publication type | A1 Journal article-refereed |

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### Keywords

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

### Cite this

*Astronomy and Astrophysics*,

*571*, [A25]. https://doi.org/10.1051/0004-6361/201321621

}

*Astronomy and Astrophysics*, vol. 571, A25. https://doi.org/10.1051/0004-6361/201321621

**Planck 2013 results. XXV. Searches for cosmic strings and other topological defects.** / Varis, Jussi; Tuovinen, Jussi; Moss, Adam (Corresponding Author); Planck Collaboration.

Research output: Contribution to journal › Article › Scientific › peer-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

AU - Planck Collaboration

N1 - Project code: 18080

PY - 2014

Y1 - 2014

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

M1 - A25

ER -