Gravitational Wave Search Resumes with Public Alerts

This post is adapted from GCN Circular 24045:

Our third observing run ("O3") began as scheduled on 1 April 2019 at 15:00 UTC. At that time the LIGO Hanford, LIGO Livingston, and Virgo observatories transitioned from engineering and commissioning to observing. All three detectors are operating at good sensitivity and stability. We are analyzing data in low latency and processing candidate transient events automatically.

As of 2 April at 20:00 UTC, we have configured our low-latency analysis pipeline to send public alerts for significant gravitational-wave transient candidates that are detected in coincidence across two or more gravitational-wave detectors.

Automated Preliminary GCN Notices will be sent immediately without any human intervention. Shortly afterward, they will be vetted by an LSC/Virgo rapid-response team and either confirmed with an Initial GCN Notice and Circular, or withdrawn with a Retraction. Retraction notices may be issued more frequently over the next few weeks as our understanding of the instrumental background improves.

For further information about vetting procedures, analysis methodology, and the contents of LIGO/Virgo public alerts — and to sign up for GCN Notices and/or Circulars — see the LIGO/Virgo Public Alerts User Guide.

This marks the beginning of the era of public alerts for the field of gravitational-wave astronomy.

— LIGO Scientific Collaboration & Virgo Collaboration