Semianalytic calculation of cosmic microwave background anisotropies from wiggly and superconducting cosmic strings

TL;DR

This paper analyzes how currents on cosmic strings influence their evolution and the resulting CMB anisotropies, providing a semi-analytic approach to improve predictions and clarify previous overestimations.

Contribution

It introduces a semi-analytic method to calculate CMB anisotropies from wiggly and superconducting cosmic strings, refining previous estimates and highlighting the importance of network parameters.

Findings

Previous models overestimated anisotropy amplitudes for wiggly strings.

Superconducting string anisotropies depend on poorly known parameters measurable in future simulations.

The modified code enables more accurate predictions of CMB signals from cosmic strings.

Abstract

We study how the presence of world-sheet currents affects the evolution of cosmic string networks, and their impact on predictions for the cosmic microwave background (CMB) anisotropies generated by these networks. We provide a general description of string networks with currents and explicitly investigate in detail two physically motivated examples: wiggly and superconducting cosmic string networks. By using a modified version of the CMBact code, we show quantitatively how the relevant network parameters in both of these cases influence the predicted CMB signal. Our analysis suggests that previous studies have overestimated the amplitude of the anisotropies for wiggly strings. For superconducting strings the amplitude of the anisotropies depends on parameters which presently are not well known - but which can be measured in future high-resolution numerical simulations.