Large scale CMB anomalies from thawing cosmic strings

Abstract

Cosmic strings formed during inflation are expected to be either diluted over super-Hubble distances, i.e., invisible today, or to have crossed our past light cone very recently. We discuss the latter situation in which a few strings imprint their signature in the Cosmic Microwave Background (CMB) Anisotropies after recombination. Being almost frozen in the Hubble flow, these strings are quasi static and evade almost all of the previously derived constraints on their tension while being able to source large scale anisotropies in the CMB sky. Using a local variance estimator on thousand of numerically simulated Nambu-Goto all sky maps, we compute the expected signal and show that it can mimic a dipole modulation at large angular scales while being negligible at small angles. Interestingly, such a scenario generically produces one cold spot from the thawing of a cosmic string loop. Mixed with anisotropies of inflationary origin, we find that a few strings of tension GU = O(1) x 10^(-6) match the amplitude of the dipole modulation reported in the Planck satellite measurements and could be at the origin of other large scale anomalies.

23 pages, 11 figures, uses jcappub. References added, matches published version

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Cited by in corpus (16)

• Exploring Cosmic Origins with CORE: Inflation
• Gravitational Wave Bursts as Harbingers of Cosmic Strings Diluted by Inflation
• Signature of inflation in the stochastic gravitational wave background generated by cosmic string networks
• Reply to "Comment on "Effects of cosmic-string framework on the thermodynamical properties of anharmonic oscillator using the ordinary statistics and the q-deformed superstatistics approaches""
• The hemispherical asymmetry from a scale-dependent inflationary bispectrum
• Irreducible cosmic production of relic vortons
• Cosmic String Detection with Tree-Based Machine Learning
• Strongly scale-dependent CMB dipolar asymmetry from super-curvature fluctuations
• Cosmic strings and other topological defects in nonscaling regimes
• CMB Cold Spot in the Planck light
• Stochastic gravitational waves from long cosmic strings
• Hemispherical Power Asymmetry of the Cosmic Microwave Background from a Remnant of a pre-Inflationary Topological Defect
• Statistical anisotropies in temperature and polarization fluctuations from a scale-dependent trispectrum
• Interferences in the Stochastic Gravitational Wave Background
• Complementary signatures of $\alpha -$attractor inflation in CMB and cosmic string Gravitational Waves
• Searching for Extremal Spots in Planck Lensing Maps