The bispectrum of cosmic string temperature fluctuations including recombination effects

Abstract

We calculate the cosmic microwave background temperature bispectrum from cosmic strings, for the first time including the contributions from the last scattering surface, using a well-established Gaussian model for the string energy-momentum correlation functions, and a simplified model for the cosmic fluid. We check our approximation for the integrated Sachs-Wolfe (ISW) contribution against the bispectrum obtained from the full sky map of the cosmic string ISW signal used by the Planck team, obtaining good agreement. We validate our model for the last scattering surface contribution by comparing the predicted temperature power spectrum with that obtained from a full Boltzmann code treatment applied to the Unconnected Segment Model of a string network. We find that including the last scattering contribution has only a small impact on the upper limit on the string tension resulting from the bispectrum at Planck resolutions, and argue that the bispectrum is unlikely to be competitive with the power spectrum at any resolution.

23 pages, 3 figures

References in corpus (7)

• CMBPol Mission Concept Study: Probing Inflation with CMB Polarization
• Small-Angle CMB Temperature Anisotropies Induced by Cosmic Strings
• Cosmic Strings and Cosmic Superstrings
• The CMB temperature bispectrum induced by cosmic strings
• Detecting Cosmic Strings in the CMB with the Canny Algorithm
• Fast Analytic Computation of Cosmic String Power Spectra
• The bispectrum of matter perturbations from cosmic strings

Cited by in corpus (8)

• CMB constraints on cosmic strings and superstrings
• Wavelet-Bayesian inference of cosmic strings embedded in the cosmic microwave background
• Multi-Scale Pipeline for the Search of String-Induced CMB Anisotropies
• Large scale CMB anomalies from thawing cosmic strings
• Cosmic String Detection with Tree-Based Machine Learning
• Estimating the Integrated Bispectrum from Weak Lensing Maps
• Stochastic gravitational waves from long cosmic strings
• Cosmic Strings-induced CMB anisotropies in light of Weighted Morphology