Nikhef involved in first detection of gravitational waves produced by colliding neutron stars

For the first time, scientists have directly detected gravitational waves — ripples in space and time — in addition to light from the spectacular collision of two neutron stars. This marks the first time that a cosmic event has been viewed in both gravitational waves and light. The discovery was made using the U.S.-based Laser Interferometer Gravitational-Wave Observatory (LIGO); the Europe-based Virgo detector; and some 70 ground- and space-based observatories. Physicists at Nikhef at Amsterdam Science Park made major contributions to the instrumentation and data analysis of this groundbreaking discovery.

Livestream at Nikhef - Credits: Marco Kraan

Neutron stars are the smallest, densest stars known to exist and are formed when massive stars explode in supernovas. As these neutron stars spiraled together, they emitted gravitational waves that were detectable for about 100 seconds; when they collided, a flash of light in the form of gamma rays was emitted and seen on Earth about two seconds after the gravitational waves. In the days and weeks following the smashup, other forms of light, or electromagnetic radiation — including X-ray, ultraviolet, optical, infrared, and radio waves — were detected. 

Nikhef director Stan Bentvelsen says the discovery is “incredibly exciting”. “Detecting the merging of neutron stars, first through gravitational waves and immediately afterwards through observations with optical telescopes provides an entirely new picture of these cosmic events. As far as I am concerned, this is the event of the century, which marks a new acquaintance with our universe.”

The observations have given astronomers an unprecedented opportunity to probe a collision of two neutron stars. For example, observations made by the U.S. Gemini Observatory, the European Very Large Telescope, and NASA’s Hubble Space Telescope reveal signatures of recently synthesized material, including gold and platinum, solving a decades-long mystery of where about half of all elements heavier than iron are produced.  

The LIGO-Virgo results are published today in the journal Physical Review Letters; additional papers from the LIGO and Virgo collaborations and the astronomical community have been either submitted or accepted for publication in various journals.

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