Characterizing the Gravitational Wave Signature from Cosmic String Cusps

TL;DR

This paper develops advanced MCMC techniques to detect and analyze gravitational wave signals from cosmic string cusps, aiding potential discoveries in string theory and cosmology.

Contribution

It introduces a parallel tempered MCMC method for efficient detection and characterization of cosmic string cusp signals in gravitational wave data.

Findings

The method can accurately recover signal parameters.

It performs well on simulated MLDC data.

Joint ground-space detections improve parameter estimation.

Abstract

Cosmic strings are predicted to form kinks and cusps that travel along the string at close to the speed of light. These disturbances are radiated away as highly beamed gravitational waves that produce a burst like pulse as the cone of emission sweeps past an observer. Gravitational wave detectors such as the Laser Interferometer Space Antenna (LISA) and the Laser Interferometer Gravitational wave Observatory (LIGO) will be capable of detecting these bursts for a wide class of string models. Such a detection would illuminate the fields of string theory, cosmology, and relativity. Here we develop template based Markov Chain Monte Carlo (MCMC) techniques that can efficiently detect and characterize the signals from cosmic string cusps. We estimate how well the signal parameters can be recovered by the advanced LIGO-Virgo network and the LISA detector using a combination of MCMC and Fisher matrix techniques. We also consider joint detections by the ground and space based instruments. We show that a parallel tempered MCMC approach can detect and characterize the signals from cosmic string cusps, and we demonstrate the utility of this approach on simulated data from the third round of Mock LISA Data Challenges (MLDCs).