CMB polarization power spectra contributions from a network of cosmic strings

Bevis, Neil; Hindmarsh, Mark; Kunz, M.; Urrestilla, Jon

doi:10.1103/physrevd.76.043005

Cited by 124 publications

(249 citation statements)

References 67 publications

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“…The Nambu-Goto string simulations are respectively labelled as MS (Martins & Shellard 2006), RSB (Ringeval et al 2007), and BOS (Blanco-Pillado et al 2011). This is contrasted with the much lower density results from lattice field theory simulations of vortex-strings labelled as MSM (Moore et al 2002) and BHKU (Bevis et al 2007b). …”

Section: Theoretical Modelling and Forecastingmentioning

confidence: 52%

Planck2013 results. XXV. Searches for cosmic strings and other topological defects

Ade¹,

Aghanim²,

Armitage-Caplan³

et al. 2014

A&A

275

191

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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 f 10 at multipole = 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/c 2 < 1.5 × 10 −7 and f 10 < 0.015 at 95% confidence that can be improved to Gµ/c 2 < 1.3 × 10 −7 and f 10 < 0.010 on inclusion of high-CMB data. For the Abelian-Higgs field theory model we find, Gµ AH /c 2 < 3.2 × 10 −7 and f 10 < 0.028. The marginalised likelihoods for f 10 and in the f 10 -Ω b h 2 plane are also presented. We have additionally obtained comparable constraints on f 10 for models with semilocal strings and global textures. In terms of the effective defect energy scale these are somewhat weaker at Gµ/c 2 < 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/c 2 ≈ 4 × 10 −7 . We have obtained upper limits on the string tension at 95% confidence of Gµ/c 2 < 9.0 × 10 −7 with modal bispectrum estimation and Gµ/c 2 < 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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Section: Theoretical Modelling and Forecastingmentioning

confidence: 52%

Planck2013 results. XXV. Searches for cosmic strings and other topological defects

Ade¹,

Aghanim²,

Armitage-Caplan³

et al. 2014

A&A

275

191

View full text Add to dashboard Cite

show abstract

“…Table III shows a comparison of 95% upper bounds on the string tension obtained by different data sets and different ways of modelling the string spectra. To date, the power spectra have been calculated using classical field theory simulations of the Abelian Higgs model [1,45] or by the Unconnected Segment Model (USM), which represents the evolving string network with moving sticks with mass and tension. The sticks have random positions and velocities, and disappear so that their overall energy density scales as t −2 .…”

Section: Parameter Constraints a Cmb Data Onlymentioning

confidence: 99%

Cosmic string parameter constraints and model analysis using small scale Cosmic Microwave Background data

Urrestilla

Bevis

Hindmarsh

et al. 2011

J. Cosmol. Astropart. Phys.

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We present a significant update of the constraints on the Abelian Higgs cosmic string tension by cosmic microwave background (CMB) data, enabled both by the use of new high-resolution CMB data from suborbital experiments as well as the latest results of the WMAP satellite, and by improved predictions for the impact of Abelian Higgs cosmic strings on the CMB power spectra. The new cosmic string spectra [1] were improved especially for small angular scales, through the use of larger Abelian Higgs string simulations and careful extrapolation. If Abelian Higgs strings are present then we find improved bounds on their contribution to the CMB anisotropies, f AH 10 < 0.095, and on their tension, GµAH < 0.57 × 10 −6 , both at 95% confidence level using WMAP7 data; and f AH 10 < 0.048 and GµAH < 0.42 × 10 −6 using all the CMB data. We also find that using all the CMB data, a scale invariant initial perturbation spectrum, ns = 1, is now disfavoured at 2.4σ even if strings are present. A Bayesian model selection analysis no longer indicates a preference for strings.

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“…They are however largely dominated by the adiabatic inflationary perturbations in TT, TE and EE power spectra and therefore are hard to detect. It is only in the B-mode sector (BB power spectrum) that the tensor topological defect perturbation could be large (Bevis et al 2007) and have a different shape (Urrestilla et al 2008) from those originating from inflation and hence be detectable (Pogosian & Wyman 2008).…”

Section: Introductionmentioning

confidence: 99%

An efficient phase-shifting scheme for bolometric additive interferometry

Charlassier¹,

Hamilton²,

Bréelle³

et al. 2009

A&A

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Context. Most upcoming CMB polarization experiments will use direct imaging to search for primordial gravitational waves through the B-modes. Bolometric interferometry is an appealing alternative to direct imaging that combines the advantages of interferometry in terms of systematic effects handling and those of bolometric detectors in terms of sensitivity. Aims. We calculate the signal from a bolometric interferometer in order to investigate its sensitivity to the Stokes parameters paying particular attention to the choice of the phase shifting scheme applied to the input channels in order to modulate the signal. Methods. The signal is expressed as a linear combination of the Stokes parameter visibilities whose coefficients are functions of the phase shifts. Results. We show that the signal to noise ratio on the reconstructed visibilities can be maximized provided the fact that the phase shifting scheme is chosen in a particular way called "coherent summation of equivalent baselines". As a result, a bolometric interferometer is competitive with an imager having the same number of horns, but only if the coherent summation of equivalent baselines is performed. We confirm our calculations using a Monte-Carlo simulation. We also discuss the impact of the uncertainties on the relative calibration between bolometers and propose a way to avoid this systematic effect.

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CMB polarization power spectra contributions from a network of cosmic strings

Cited by 124 publications

References 67 publications

Planck2013 results. XXV. Searches for cosmic strings and other topological defects

Planck2013 results. XXV. Searches for cosmic strings and other topological defects

Cosmic string parameter constraints and model analysis using small scale Cosmic Microwave Background data

An efficient phase-shifting scheme for bolometric additive interferometry

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