Gravitational Wave Network
Planned Lifetime: 2028+
End of Operations: No specific requirement
Data Archive: GW Open Science Center
LIGO, Virgo, and KAGRA comprise the advanced gravitational wave detector network, often referred to as "LVK". LIGO is operated by the National Science Foundation, Virgo by the European Gravitational Wave Observatory, and KAGRA by the ministry of Education, Culture, Sports, Science and Technology-Japan (MEXT). Together they detect, localize, and characterize the coalescence of compact binary mergers, continuous gravitational waves, and burst gravitational waves.
| Interferometers | Location | Size | Joined GW Network | BNS Range (O5) |
|---|---|---|---|---|
| Laser Interferometer Gravitational-Wave Observatory (LIGO) | Hanford, WA, USA Livingston, LA, USA | 4 km | 2015 | 240-325 Mpc |
| Virgo Gravitational Wave Interferometer (Virgo) | Pisa, Italy | 3 km | 2017 | 90-130 Mpc |
| Kamioka Gravitational Wave Detector (KAGRA) | Kamioka-cho, Hida-city, Gifu-prefecture, Japan | 3 km | 2020 | 25-90 Mpc |
GCN Notice Types in GCN Classic and GCN Classic Over Kafka: LVK public alerts user guide. Additional documentation on LVK GCN Classic notices can be found here.
| Type | Contents | Latency |
|---|---|---|
LVC_EARLY_WARNING | A pre-merger alert. | -1-0 minutes |
LVC_PRELIMINARY | First notice, timestamp alert, location probability sky map; all automated processing. | 1–10 minutes |
LVC_INITIAL | Improved SkyMap now available (human-involved processing). | 4–24 hours |
LVC_UPDATE | Ultimate refined sky map (more detailed offline processing). | ~1–7 days |
LVC_RETRACTION | After human analysis/evaluation, a retraction will be issued if trigger is not astrophysical. | 1 hour–1 day |
JSON-Serialized GCN Notices Types in GCN Kafka:
LVK distributes alerts for the detection of gravitational wave events. These notices are published on the GCN Kafka topic igwn.gwalert.
See the LVK Documentation for more information on the properties defined in the schema. Detailed description of LVK notice types can be found in the LVK public alerts user guide.
| Type | Contents | Latency |
|---|---|---|
EARLYWARNING | A pre-merger alert. | -1-0 minutes |
PRELIMINARY | First notice, timestamp alert, location probability sky map; all automated processing. | 1–10 minutes |
INITIAL | Improved SkyMap now available (human-involved processing). | 4–24 hours |
UPDATE | Ultimate refined sky map (more detailed offline processing). | ~1–7 days |
RETRACTION | After human analysis/evaluation, a retraction will be issued if trigger is not astrophysical. | 1 hour–1 day |
Common GCN Circular Types:
| Type | Latency | Example |
|---|---|---|
| Identification of a GW trigger | 4-24 hours | LIGO/Virgo/KAGRA S251117dq |
| Updated sky localization of a GW trigger | 1-7 days | LIGO/Virgo/KAGRA S251117dq |
| Retraction of a GW trigger | 1 day | LIGO/Virgo/KAGRA S251017di |
Predicted Annual Detection Rates for O5a:
| Merger Class | Public Alerts per Calendar Year | Median 90% Credible Area [deg2] |
|---|---|---|
| Binary Neutron Star | 5 (0–14) | 1260 |
| Neutron Star-Black Hole | 11 (3–28) | 1540 |
| Binary Black Hole | 520 (230–1140) | 1238 |
O5 predictions from the LVK observing capabilities documentation. Uncertainties are the 90% confidence interval, including Poisson uncertainty. This document is updated periodically for future observing runs.