LIGO’s and Virgo’s third observing run has spotted a black hole eating a mystery object that enables new tests of Einstein's theory of general relativity. The event is the merger of a 23-solar-mass black hole with an object 9 times lighter.
The researchers are still unclear on the nature of the second object. Its mass puts it in the gap between the heaviest known neutron stars and the lightest known black holes, making it difficult to identify. Together, the pair challenges today's understanding of how such systems are created and evolve.
“GW190814 is an unexpected and a really exciting discovery,” said in a statement Abhirup Ghosh, a post-doctoral researcher in the Astrophysical and Cosmological Relativity division at the Max Planck Institute for Gravitational Physics (Albert Einstein Institute; AEI) in Potsdam.
“It is unique because of two outstanding features. Never before have we witnessed a gravitational-wave signal from a system in which the individual masses are this different: a black hole 23 times the mass of our Sun merging with an object just 2.6 times the mass of the Sun."
The scientists also used GW190814 to look for deviations of the signal from predictions of Einstein’s general theory of relativity. They found that even this strange signal that identifies a new type of binary merger follows the theory’s predictions.
“These harmonics – seen in GW190814 only for the second time ever – allow us to more precisely measure some astrophysical properties of the binary system and enable new tests of Einstein’s theory of general relativity," said Jonathan Gair, group leader in the Astrophysical and Cosmological Relativity division at the AEI in Potsdam.
This event is the third reported from the third observing run (O3) of the LIGO’s and Virgo’s international gravitational-wave detector network. The LIGO and Virgo researchers have released alerts for 56 possible gravitational-wave events in O3 and are examining all of them. So far, three have been confirmed.