The gravity wave detections were in 2015 when Laser Interferometer Gravitational-Wave Observatory (LIGO) researchers detected the impact of two black holes.
On October 1st, LIGO’s Hanford (LHO) and Livingston (LLO) detectors will temporarily halt observations to undergo a series of instrument upgrades and fixes. This kind of “commissioning break” sometimes occurs during LIGO’s long observing runs. The current run, O3, began on April 1 2019, when Virgo, the European-based gravitational-wave detector, located at the European Gravitational Observatory (EGO) in Italy, also started observing. Virgo is also pausing this month to perform upgrades that will improve their sensitivity and their uptime. All three detectors will resume operations on November 1st.
By July 31st, 2019, LIGO had sent out 25 alerts to possible detections, three have since been retracted, leaving us with 22 ‘candidate’ gravitational wave events. We call them “candidates” because we still need time to vet all of them. If all candidates are verified, then the number of detections made by LIGO in just the first third of O3 will double the number of detections made in its first two runs combined.
Halfway through LIGO’s O3 observing run there were over thirty BH-BH merger detections and a handful of NS-NS events.
Black Hole Colliding With and Devouring a Neutron Star
Three gravity wave detectors in the United States and Italy detected a pulse of gravitational waves—ripples in space itself—apparently set off when a black hole and a neutron star spiraled into each other about 900 million light-years away. Observers had previously spotted numerous mergers of black holes and one merger of neutron stars, but never a combination. The new find could give new insights into neutron stars, which are made of the densest matter in the cosmos.
“This is a huge milestone—if it stands up,” says Patrick Brady, spokesperson for the more than 1300 scientists working with the Laser Interferometer Gravitational-Wave Observatory (LIGO), which has twin detectors in Hanford, Washington, and Livingston, Louisiana. The new observation was made by LIGO and Virgo, a gravitational wave detector near Pisa, Italy, which itself hosts more than 400 scientists.
Three Black Holes Collision Course
Astronomers working with data from the space-based Chandra X-ray Observatory said this week (September 25, 2019) that they’ve located three supermassive black holes on a collision course.