Light from two colliding neutron stars

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LIGO and Virgo make first detection of gravitational waves produced by colliding neutron stars. Scientists from the UW contributed to this discovery that marks first cosmic event observed in both gravitational waves and light.

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.

 

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.

 

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”.

 

– It is tremendously exciting to experience a rare event that transforms our understanding of the workings of the universe – says France A. Córdova, director of the National Science Foundation (NSF), which funds LIGO. – This discovery realizes a long-standing goal many of us have had, that is, to simultaneously observe rare cosmic events using both traditional as well as gravitational-wave observatories. Only through NSF’s four-decade investment in gravitational-wave observatories, coupled with telescopes that observe from radio to gamma-ray wavelengths, are we able to expand our opportunities to detect new cosmic phenomena and piece together a fresh narrative of the physics of stars in their death throes.

 

More than 1,200 scientists and some 100 institutions from around the world participate in the effort through the LIGO Scientific Collaboration, which includes the GEO Collaboration and the Australian collaboration OzGrav. Additional partners are listed at http://ligo.org/partners.php.

 

The Virgo collaboration consists of more than 280 physicists and engineers belonging to 20 different European research groups.

 

“GW170817: Observation of gravitational waves from a binary neutron star merger”, “Physical Review Letters”.

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