Searching for gravitational wave bursts from cosmic string cusps with the Parkes Pulsar Timing Array

TL;DR

This paper develops a new detection algorithm for gravitational wave bursts from cosmic string cusps using pulsar timing data, applies it to Parkes PTA data, finds no convincing signals, and sets new upper limits on cosmic string tension.

Contribution

The paper introduces a novel detection method for GW bursts from cosmic string cusps and applies it to real PTA data, establishing independent constraints on cosmic string tension.

Findings

No convincing GW burst detections in Parkes PTA data.

Upper limits on cosmic string tension Gμ ~ 10^{-5}.

Method demonstrates potential for future SKA observations.

Abstract

Cosmic strings are potential gravitational wave (GW) sources that can be probed by pulsar timing arrays (PTAs). In this work we develop a detection algorithm for a GW burst from a cusp on a cosmic string, and apply it to Parkes PTA data. We find four events with a false alarm probability less than 1%. However further investigation shows that all of these are likely to be spurious. As there are no convincing detections we place upper limits on the GW amplitude for different event durations. From these bounds we place limits on the cosmic string tension of G mu ~ 10^{-5}, and highlight that this bound is independent from those obtained using other techniques. We discuss the physical implications of our results and the prospect of probing cosmic strings in the era of Square Kilometre Array (SKA).