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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 took place in October 2019, and then the run continued through 27 Mar 2020 17:00 UTC. This is about a month before the planned end date (of 30 April), due to the constraints from COVID-19.

This decision to halt O3 was not an easy one, however the current worldwide COVID-19 pandemic demands that we make public health and safety our top priority.

The LIGO Laboratory, LIGO Scientific Collaboration, EGO, and Virgo Collaboration leadership are working to ensure that the transition out of O3 is smooth and preserves the potential science to be done with LV data. In particular, this means carrying out critical detector measurements and calibrations needed to ensure O3b data integrity and quality (as long as those measurements are done on a short time scale). Note that no further Public Alerts will be issued after March 27th, until detector operations resume.

We currently plan to keep the LIGO and EGO computing clusters running remotely to allow continued LVC data processing, work on papers and system upgrades. At this point, it’s impossible to say anything about impacts to the upgrade plans for LIGO and Virgo (including A+ and AdV+) beyond noting that there will be impacts.

In spite of the early suspension, the O3 run has been a tremendous success and we look forward to the science to come from the O3 events and the future observing runs with the gravitational-wave detector network.


If you have any questions, please contact the Spokespersons:
  • Patrick Brady (Spokesperson, LIGO Scientific Collaboration); lsc-spokesperson@ligo.org
  • Jo van den Brand (Spokesperson, Virgo Collaboration); virgo-spokesperson@ego-gw.it

Additional information on the status of LIGO Laboratory operations in reference to COVID-19 can be found here.



Observing Plan information prior to O3 suspension

The information below contains historical documents relvant to LIGO-Virgo observing plans and public alerts. In light of the suspension of O3 operations one month earlier than planned and the ongoing COVID-19 pandemic, dates and plans discussed in these documents will likely require revision.

observing plan timeline

O3 observing run timeline

  • Start date: 1 April 2019
  • Commissioning break: 1-31 October 2019
  • Observing suspended: 27 March 2020

Public Alerts in O3

  • Public Alerts for O3 ended on 27 March 2020.
  • Alerts are issued through the GCN/TAN system.
  • For more information and usage examples, see the LIGO/Virgo Public Alerts User Guide.
  • The official candidate event database is GraceDB.
  • For the general public, a more accessible view is maintained on the Chirp website; mobile apps are also available there.

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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