Signal of Cosmic Strings in Cross-Correlation of 21-cm Redshift and CMB Polarization Maps

TL;DR

This paper proposes a method to detect cosmic strings by analyzing the cross-correlation between 21-cm redshift and CMB polarization maps, identifying non-Gaussian signals through matched filtering, even for low-tension strings.

Contribution

It introduces a novel approach to detect cosmic string wakes in early universe signals using cross-correlation and matched filtering techniques.

Findings

Cosmic string signals can be extracted from cross-correlation maps.

Detection is possible for strings with tensions below current bounds.

The method effectively distinguishes string signals from Gaussian background fluctuations.

Abstract

We study the signal of cosmic string wakes present before the time of reionization in the cross-correlation signal of 21-cm redshift and B-mode CMB polarization maps. The specific non-Gaussian signal of strings in the position space cross-correlation maps can be extracted by means of a matched filtering analysis. Signals of strings with tension somewhat lower than those corresponding to the current upper bound can be identified when embedded in a background of Gaussian fluctuations from a Planck best-fit LCDM model.