A tilted black hole rotating around a misaligned axis has been discovered in our galaxy, challenging theories of black hole formation.
the black hole and its companion star form a system called MAXI J1820+070, which lies about 10,000 light-years from Earth. The system was first spotted by NASA Chandra X-ray Observatory in 2018. But recent optical observations from the Nordic Optical Telescope in the Canary Islands revealed that the black hole is behaving in a way that defies astronomers’ expectations.
By studying the orientation of the jets of ionized matter emitted by the poles of the black hole, Juri Poutanen, an astronomer at the University of Turku in Finland, discovered that the black hole rotates around an axis tilted by at least 40 degrees. to the plane in which the block hole orbits its companion star. This is the largest misalignment ever reported, said Poutanen and his colleagues. in a report.
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“We observed the black hole MAXI J1820+070 X-ray binary with a high-precision optical polarimeter,” Poutanen told Space.com in an email. “Using these data, we determined the position angle of the binary orbit on the sky. The spin orientation of the black hole can be obtained from radio and X-ray observations of relativistic jets previously observed from the system.”
By combining all this information, the scientists were able to determine the angle between the axis of the binary orbit and the spin of the black hole, he added.
Theoretical models expect binary systems, such as black holes orbited by stars from which they suck material, to revolve around aligned axes perpendicular to their common orbital plane.
Previously, astrophysicists expected that these axes could only be “marginally” misaligned, the scientists said in the statement.
The question remains what caused the misalignment in MAXI J1820+070. Scientists believe that, unlike current models of black holes forming from supernova explosions, MAXI J1820+070’s black hole must have been “kicked” in the explosion that caused it.
The authors found this misalignment unlikely to occur at a later stage, because the accretion of matter between two bodies in a binary system and the gravitational forces between them “always bring the axes into alignment,” the authors said. .
The finding could have wider implications for black hole science, the scientists said, because such misalignments could bias measurements of black hole masses and spins.
The paper was published in the journal Science on Thursday 24 February.