Rapid alerts for following up gravitational wave event candidates

TL;DR

This paper describes the development and implementation of a low-latency gravitational wave alert system that enables rapid follow-up observations of astrophysical events, improving multi-messenger astronomy capabilities.

Contribution

It introduces the first complete low-latency GW data analysis and alert system, detailing its design, operational considerations, and lessons learned for future improvements.

Findings

First successful implementation of low-latency GW alert system

Enabled rapid alerts to observing partners for follow-up

Provided operational insights for future GW alert systems

Abstract

Gravitational waves carry unique information about high-energy astrophysical events such as the inspiral and merger of neutron stars and black holes, core collapse in massive stars, and other sources. Large gravitational wave (GW) detectors utilizing exquisitely sensitive laser interferometry--namely, LIGO in the United States and GEO 600 and Virgo in Europe--have been successfully operated in recent years and are currently being upgraded to greatly improve their sensitivities. Many signals are expected to be detected in the coming decade. Simultaneous observing with the network of GW detectors enables us to identify and localize event candidates on the sky with modest precision, opening up the possibility of capturing optical transients or other electromagnetic counterparts to confirm an event and obtain complementary information about it. We developed and implemented the first complete low-latency GW data analysis and alert system in 2009-10 and used it to send alerts to several observing partners; the system design and some lessons learned are briefly described. We discuss several operational considerations and design choices for improving this scientific capability for future observations.