A network of three gravitational wave detectors

There are now three laser interferometers observing the universe with gravitational waves! The first direct detection of gravitational waves by the two Advanced Ligo detectors in 2015 was recently confirmed by a third event (see here for details). Having only two interferometers recording the events, the localisation uncertainties of the sources was very challenging (see the right figure below). This is now going to change: "Tuesday August 1st 2017, the VIRGO detector located at the European Gravitational Observatory (EGO) in Cascina (near Pisa, Italy) has officially joined the “Observation Run 2” (O2) and is now taking data alongside the American-based twin LIGO detectors. The O2 data taking period will last until August 25th." (from Virgo).
The expected improvement in the localisation accuracy is visualized in the (simulation based) estimate by Leo Singer shown below (left figure, from Ligo). We keep our fingers crossed that the joint duty-cycle of the three detectors is sufficiently high and that nature is kind enough to send us another strong gravitational wave signal in the few weeks until the end of the current data taking run...