More than 30 scientists from The University of Western Australia’s node of the ARC Centre of Excellence for Gravitational Wave Discovery (OzGrav) are part of an international team that has discovered four new colliding black holes in the Universe.
This includes the detection of the most massive and distant gravitational-wave source ever to be observed and brings the number of black hole collisions detected by the team to 10.
The data, presented at the Gravitational Wave Physics and Astronomy Workshop in Maryland, Washington DC, and in a series of journal publications to coincide with the meeting, represents gravitational waves from a total of 10 stellar-mass binary black hole mergers and one merger of neutron stars, which are the dense, spherical remains of stellar explosions.
UWA Research Fellow Dr Xu (Sundae) Chen said with each new detection, more could be learnt about the extraordinary number of black holes which the team had never expected to find.
“The detections also help to answer questions about the theory of gravity, the formation of galaxies, and how heavy elements (including gold and platinum) are produced,” Dr Chen said.
Dr Chen is excited about the most powerful event because it happened around five billion years before the earth formed.
“It was the biggest explosion observed in astronomy which turned five times the mass of the sun into pure gravitational energy in the space of less than a second,” she said.
The findings build on previous work of the scientists. Between 12 September 2015 and 19 January 2016, during the first LIGO observing run since undergoing upgrades in a program called Advanced LIGO, gravitational waves from three binary black hole mergers were detected.
The second, which lasted from November 30, 2016, to August 25, 2017, yielded one binary neutron star merger and seven additional binary black hole mergers, including the four new gravitational-wave events being reported now.
One of the new events, which was detected by the global network formed by the LIGO and Virgo observatories, was very precisely pinpointed in the sky. The position of the binary black holes, located 2.5 billion light-years from Earth, was identified in the sky with a precision of 39 square degrees. That makes it the next best localised gravitational-wave source after the neutron star merger.
(Provided by The University of Western Australia)
