Straight to the source: the LIGO-Virgo global network of interferometers opens a new era for gravitational wave science


A fourth gravitational-wave signal coming from the merger of two stellar mass black holes located about 1.8 billion light-years away was detected on the 14th of August 2017, at 10:30:43 UTC. GW170814 is the first event observed by the global 3-detector network, including not only the two twin Advanced LIGO detectors but the Advanced Virgo detector as well.

Following a multi-year upgrade programme and several months of commissioning, the Advanced Virgo detector joined the LIGO “Observation Run 2” data-taking period on the 1st of August. The three instruments worked together until the 25th of August.

GW170814 demonstrates the potential of a 3-detector network, both in terms of localization of a source in the sky and in terms of the testing of Einstein’s theory of general relativity. The best GW170814 skymaps, computed by an analysis that uses all of the available information from the three instruments, cover just 60 square degrees (to be compared with several hundreds of square degrees for the LIGO-only network) and GW170814 data have allowed the LIGO-Virgo collaboration to probe, for the first time, the polarization of gravitational waves.

Therefore, GW170814 holds great promise for the future of multimessenger astronomy. Additional results, based on data from the three-detector network, will be announced in the near future by the LIGO-Virgo Collaboration; the analysis of the data is currently being finalized.


The APC has been at the front line on all fronts of this discovery, with the support of Labex UnivEarthS on the projects E3: Geophysics and gravitational wave interferometric detectors and I10: From evolving binaries to the merging of compact objects . We have contributed both to the design and construction of the Advanced Virgo detector and to the analysis and interpretation of the data.

We will soon be publishing an article highlighting the work of APC on the project, to explain the specific contributions our teams have made to the ITF telescope, data analysis and optical design parts.


Download the press release of the LIGO and Virgo collaborations.

GW170814: A three-detector observation of gravitational waves from a binary black hole coalescence. The LIGO Scientific Collaboration and The Virgo Collaboration, Physical Review Letters.