The LIGO Livingston Observatory has detected the second ever set of gravitational ripples from the collision of two neutron stars.
LIGO Livingston is part of a gravitational-wave network that includes LIGO (the Laser Interferometer Gravitational-wave Observatory), funded by the National Science Foundation (NSF), and the European Virgo detector.
New research confirms that this event was indeed likely the result of a merger of two neutron stars. This would be only the second time this type of event has ever been observed in gravitational waves.
“From conventional observations with light, we already knew of 17 binary neutron star systems in our own galaxy and we have estimated the masses of these stars,” says Ben Farr, a LIGO team member based at the University of Oregon.
Farr continued: “What’s surprising is that the combined mass of this binary is much higher than what was expected.”
The first such observation took place in August of 2017. The most recent merger did not result in any light being detected. However, through an analysis of the gravitational-wave data alone, researchers have learned that the collision produced an object with an unusually high mass.
“We have detected a second event consistent with a binary neutron star system and this is an important confirmation of the August 2017 event that marked an exciting new beginning for multi-messenger astronomy two years ago,” says Jo van den Brand, Virgo Spokesperson and professor at Maastricht University, and Nikhef and VU University Amsterdam in the Netherlands. Multi-messenger astronomy occurs when different types of signals are witnessed simultaneously, such as those based on gravitational waves and light.
Simulation of the binary neutron star coalescence GW190425. This shows a numerical simulation representing the binary neutron star coalescence and merger which resulted in the detected gravitational-wave event GW190425. The two neutron stars shown here have properties consistent with the detection made by the Advanced LIGO/Virgo detectors.