CMB power spectra from cosmic strings: predictions for the Planck satellite and beyond

TL;DR

This paper improves predictions of cosmic string contributions to CMB power spectra at small scales relevant for Planck, using larger simulations and extrapolations to accurately estimate effects up to multipole l=4000.

Contribution

It introduces enhanced simulation and modeling techniques to better predict cosmic string effects on CMB spectra at high multipoles, extending previous work.

Findings

String contribution at 10% at l=10 exceeds primary anisotropies at l>3500

Power-law behavior observed for l>3000 in temperature spectrum

Astrophysical effects like Sunyaev-Zeldovich impact detectability at small scales

Abstract

We present a significant improvement over our previous calculations of the cosmic string contribution to cosmic microwave background (CMB) power spectra, with particular focus on sub-WMAP angular scales. These smaller scales are relevant for the now-operational Planck satellite and additional sub-orbital CMB projects that have even finer resolutions. We employ larger Abelian Higgs string simulations than before and we additionally model and extrapolate the statistical measures from our simulations to smaller length scales. We then use an efficient means of including the extrapolations into our Einstein-Boltzmann calculations in order to yield accurate results over the multipole range 2 < l < 4000. Our results suggest that power-law behaviour cuts in for l > 3000 in the case of the temperature power spectrum, which then allows cautious extrapolation to even smaller scales. We find that a string contribution to the temperature power spectrum making up 10% of power at l=10 would be larger than the Silk-damped primary adiabatic contribution for l > 3500. Astrophysical contributions such as the Sunyaev-Zeldovich effect also become important at these scales and will reduce the sensitivity to strings, but these are potentially distinguishable by their frequency-dependence.