Cosmic string bursts in LISA

Abstract

Cosmic string cusps are sources of short-lived, linearly polarised gravitational wave bursts which can be searched for in gravitational wave detectors. We assess the capability of LISA to detect these bursts using the latest LISA configuration and operational assumptions. For such short bursts, we verify that LISA can be considered as ``frozen", namely that one can neglect LISA's orbital motion. We consider two models for the network of cosmic string loops, and estimate that LISA should be able to detect 4-30 bursts per year assuming a string tension $Gμ\approx 10^{-10.6} - 10^{-10.1}$ and detection threshold $\rm{SNR} \ge 20$. Non-detection of these bursts would constrain the string tension to $Gμ\lesssim 10^{-11}$ for both models.