Updated constraints on superconducting cosmic strings from the astronomy of fast radio bursts

Batool Imtiaz,Yi-Fu Cai,Rui Shi

doi:10.1140/epjc/s10052-020-8064-x

Abstract

In this article we update constraints on superconducting cosmic strings (SCSs) in the light of the recent observational developments of fast radio bursts (FRBs) astronomy. Assuming strings follow an exponential distribution characterized by a current, we show that two parameters in our context, which are the characteristic tension (Gmu ) and a parameter which describes the aforementioned exponential distribution (I_c), can be constrained by FRB experiments. Particularly, we investigate data sets from Parkes and ASKAP. We looked at a parameter space where Gmu sim [10^{-17}, 10^{-12}] and I_csim [10^{-1}, 10^{2}] GeV, and found our results show that Parkes jointly with ASKAP can constrain the parameter space for SCSs.

Highlights

Chrotron maser emission from young magnetars in supernova remnants [17], radiation from cosmic string cusps [18], charged primordial black hole binaries coalescence [19], and many other possible models [20,21,22,23]
The CMB analyses based on the Wilkinson Microwave Anisotropy Probe (WMAP) and the South Pole Telescope can lead to an upper bound on the string tension of Gμ < 1.7 × 10−7 [34], and this bound was later improved to Gμ < 1.3 × 10−7 with the data from the Planck satellite [35]
The electromagnetic backreaction becomes important when it is comparable with the string tension itself, and this leads to a cutoff on the frequency of the emitted radiation as addressed in [31], which is typically above the observational region for the fast radio bursts (FRBs) astronomy

Summary

Introduction

Cosmic strings [24], being one-dimensional topological defects, formed during the early evolution of the universe [25]. In a much realistic situation, one would expect a probability distribution for the currents inside various strings in the universe To explore this possibility, in this article we put forward a novel parameterization for SCSs, in which the currents are assumed to follow the exponential distribution. The probability for cosmic strings with larger current becomes lower, which indicates that SCSs can hardly be formed at extremely high-energy scales Such an exponential distribution as considered in the present work is not based on a particular fundamental theory, but generally from the intuitive observation that the lifetime of a string with the fixed tension should be shorter if it would carry a larger current due to the energy loss of both gravitational and electromagnetic radiations. We followed the setups of the Parkes multi-beam receiver and ASKAP survey.

Characteristics of cosmic strings

Parametrization of SCSs

Radiations from string loops

Event rate of burst

Numerical results

Conclusion and discussion