Global 21cm Absorption Signal from Superconducting Cosmic Strings

TL;DR

This paper investigates how superconducting cosmic strings influence the global 21cm absorption signal, revealing potential amplification of features during cosmic dawn and dark age that align with EDGES observations.

Contribution

It provides a detailed calculation of 21cm absorption features caused by superconducting cosmic strings with critical current, highlighting their dependence on string tension and observational relevance.

Findings

Amplification of 21cm absorption features at specific redshifts

Potential explanation for EDGES signal

Dependence of effects on string tension Gμ

Abstract

Superconducting cosmic strings emit electromagnetic waves between the times of recombination and reionization. Hence, they have an effect on the global 21cm signal. We compute the resulting absorption features, focusing on strings with critical current, study their dependence on the string tension $\mu$, and compare with observational results. For string tensions in the range of $G \mu = 10^{-10}$, where $G$ is Newton's gravitational constant, there is an interesting amplification of the two characteristic absorption features, one during the cosmic dawn, $z \lesssim 30$, and the other during the cosmic dark age, $z \sim 80$, the former being comparable in amplitude to what was observed by the EDGES experiment.