Lightest black hole merger detected

16 November 2017

Black holes

Known black holes as of Nov 15
(Credit: LIGO)

Scientists searching for gravitational waves have confirmed yet another detection from their fruitful observation run earlier this year. The latest discovery, dubbed GW170608, was produced by the merger of two relatively light black holes, 7 and 12 times the mass of the sun, at a distance of about a thousand million light-years from Earth.

The merger left behind a final black hole 18 times the mass of the sun, meaning that energy equivalent to about 1 solar mass was emitted as gravitational waves during the collision.

In a new paper published today, the LIGO Scientific Collaboration and the Virgo Collaboration announced this latest gravitational wave discovery – the collision of the lightest pair of binary black holes seen by the collaborations’ detectors since the first detection in September 2015.

Dr John Veitch, who is co-chair of LIGO’s Compact Binary Coalescence Search Group and Research Fellow at the University of Glasgow’s School of Physics and Astronomy said:

"GW170608 is the lightest pair of black holes that we have detected so far, which provides us with new opportunities to explore the crossover between gravitational wave astronomy and more conventional forms of astronomy."

Prof Sheila Rowan, director of the University of Glasgow Institute for Gravitational Research, said: “Our most recent observing run is still giving us new surprises - and extending the black hole family tree into new branches.”

Professor Martin Hendry, head of the University of Glasgow’s School of Physics and Astronomy, said: “This latest discovery will help astronomers to better compare and contrast the properties of black holes observed with gravitational waves with the properties of similar-mass black holes previously detected indirectly with X-ray observations.”

Despite their relatively diminutive size, GW170608’s black holes will greatly contribute to the growing field of “multimessenger astronomy”, where gravitational wave astronomers and electromagnetic astronomers are working together to learn more about these exotic and mysterious objects. 

The UK’s involvement with Gravitational Waves research is led by the Universities of Birmingham, Cardiff and Glasgow.

Notes to Editors

This event, detected by the two NSF-supported LIGO detectors at 02:01:16 UTC on June 8, 2017 (or 10:01:16 pm on June 7 in US Eastern Daylight time), was actually the second binary black hole merger observed during LIGO’s second observation run since being upgraded in a program called Advanced LIGO. But its announcement was delayed due to the time required to understand two other discoveries: a LIGO-Virgo three-detector observation of gravitational waves from another binary black hole merger (GW170814) on August 14, and the first-ever detection of a binary neutron star merger (GW170817) in light and gravitational waves on August 17.

A paper describing the newly confirmed observation, “GW170608: Observation of a 19-solar-mass binary black hole coalescence,” authored by the LIGO Scientific Collaboration and the Virgo Collaboration has been submitted to 'The Astrophysical Journal Letters' and is available to read on the arXiv. Additional information for the scientific and general public is available here.

Read more about this detection.

What’s next

The LIGO and Virgo detectors are currently offline for further upgrades to improve sensitivity. Scientists expect to launch a new observing run in fall 2018, though there will be occasional test runs during which detections may occur.

LIGO and Virgo scientists continue to study data from the completed "O2" observing run, searching for other events already "in the can," and are preparing for the greater sensitivity expected for the fall O3 observing run.

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More information on Gravitational Waves

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