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Observing Plans and Public Alerts

LIGO-Virgo Observing plans

The LIGO and Virgo teams are working on improving the performance of their instruments, with the objective of starting the third observing run (O3) early in 2019. The current schedule for commissioning, engineering runs, and observing is sketched in the graphic below (LIGO DCC: G1801056; last updated 14 November 2018).

We have a revised but reasonably firm schedule for the milestones relevant to the start of O3, as presented at a conference call with interested Observers on 15 November 2018. The agenda for that call contains links to presentations and documentation which will be of interest to all observers. A brief summary follows.

The next event of interest will be our engineering run ER13, planned for 14 Dec 2018 08:00 US Pacific time to 18 December 06:00 US Pacific time.

Good progress has been made on commissioning the two LIGO and one Virgo instruments, and all three have exceeded the best sensitivity seen in O2. However, additional work is needed to reach the target sensitivities and operate reliably. For this reason we are shifting the planned start date of ER 14 to early March and the start of O3 to late March (ER14 should last about one month). These dates are shown in the timeline below.

The team working on low-latency alerts is making excellent progress. A detailed update on Public Alerts was given on 15 November; the relevant presentation and LIGO/Virgo Public Alerts User Guide are publically available. We are will use the normal public GCN network for distributing the GW alerts.

Note that during Engineering Runs and other times of stable instrument operation prior to the O3 start, no automatic alerts will be sent except as non-astrophysical tests. If a gravitational-wave candidate is identified during a time when the instruments are operating well enough to allow an astrophysical interpretation, the LIGO-Virgo Collaboration will first manually check the data for validity. If the candidate is of significant interest, the LIGO-Virgo Collaboration will then manually issue a public alert, with subsequent updates as information becomes available.

A one-hour telecon with all interested scientists will be announced as a followup on preparations for O3. An agenda and the specifics for connecting will be posted at the OpenLVEM web page and sent to the email alias for that group.

If you have any questions, please contact the Spokespersons:


observing plan timeline

Further information on the planned sensitivity, possible detection rates, and other details of interest can be found in the presentations for the Observer Town Halls of March and April 2018. An overview for LIGO, Virgo, and KAGRA Observing Scenarios can be found at this Living Reviews in Relativity article.


Open Public Alerts in O3

The LIGO-Virgo (LV) Collaborations will issue Open, Public Alerts (OPA) for gravitational-wave transient event detections, starting with the next observing run of the instruments early in 2019. OPAs will 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, in consistency with our data management plan.

In anticipation, we invite the physics and astronomy community interested in the multi-messenger aspects of gravitational wave science to join a new "open forum". This Open LV-EM 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 held two Town Hall meetings for the community interested in the multi-messenger science enabled by the LIGO-Virgo OPAs: one in Cambridge, Massachusetts (March 16-17, 2018), the other in Amsterdam, Netherlands (April 12-13, 2018). The presentations are a good source of additional information on the plans of the Collaborations and some Observers. Pointers to presentations made at those Town Halls can be found at this web page.

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:


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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