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Observing Plans and Public Alerts

LIGO, Virgo and KAGRA Observing Run Plans

The Advanced LIGO and Advanced Virgo gravitational-wave detectors began their third observing run (O3) on April 1, 2019. A break in the run for detector work has been scheduled for the full month of October, and then the run is expected to continue through April 30, 2020. The KAGRA detector may join the later part of the O3 run as commissioning progress permits.

The document Advanced LIGO, Advanced Virgo and KAGRA observing run plans presents our current best estimate of the plausible observing scenarios for the third (O3), fourth (O4) and fifth (O5) observing runs. It shows:

  • the planned observing timeline for the Advanced LIGO, Advanced Virgo and KAGRA detectors
  • target strain sensitivities as a function of frequency for each observing run, including the planned upgrades of the Advanced LIGO and Advanced Virgo detectors
  • achievable range for binary neutron star (BNS), neutron star–black hole (NSBH), binary black hole (BBH), and unmodeled signals

This document supersedes the schedule projection contained in the December 2018 Living Reviews article, Prospects for observing and localizing gravitational-wave transients with Advanced LIGO, Advanced Virgo and KAGRA. An updated version of the complete Living Reviews article is a work in progress, and will include the network's expected ability to localize gravitational-wave transient signals (as sky localization probability area, distance and volume), and to detect BNS, NSBH, and BBH systems (as number of detections per calendar year of running).

The current schedule projection for the O3 and future observing runs is summarized in the graphic below. Note that there is significant uncertainty in the start and end dates of future observing runs (represented here by shading) and in the actual sensitivities (BNS ranges given here) which will be achieved.

observing plan timeline

Further information on the planned sensitivity, possible detection rates, and other details of interest can be found in the LIGO/Virgo Public Alerts User Guide and in the presentations given in the Observer Town Halls of March and April 2018.


Public Alerts in O3

The LIGO and Virgo Collaborations (LVC) have begun issuing prompt Public Alerts for gravitational-wave transient event detections, starting with the O3 observing run which began in April 2019. These alerts enable the physics and astronomy community to pursue multi-messenger observations of gravitational-wave sources and maximize the science reach of the gravitational-wave instruments, consistent with our data management plan. Alerts are issued as Notices and Circulars distributed through the GCN/TAN system. For more information and usage examples, see the LIGO/Virgo Public Alerts User Guide.

We invite the physics and astronomy community interested in the multi-messenger aspects of gravitational wave science to join the Open LV-EM forum. This forum has no MoU requirements for joining or for participation. It is intended to facilitate the free exchange of information and ideas among gravitational-wave, electromagnetic, neutrino, and cosmic-ray astronomers. Details on how to join can be found here.

We look forward to your participation in this new and exciting era of multi-messenger science with gravitational-waves.


If you have any questions, please contact the Spokespersons:

O3 observing run timeline

  • Start date: 1 April 2019
  • Commissioning break: 1-31 October 2019
  • End date: 30 April 2020 (expected)

triangulation of GW170817

GW170817 Localization and Triangulation Annuli. We can pinpoint sources like GW170817 much more accurately now that we can triangulate the signal between Hanford, Livingston, and Virgo. The rapid Hanford-Livingston localization is shown in blue, and the final Hanford-Livingston-Virgo localization is in green. The gray rings are one-sigma triangulation constraints from the three detector pairs. [Credit: LIGO/Virgo/NASA/Leo Singer (Milky Way image: Axel Mellinger)]

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