(ORDO NEWS) — A small black hole that just hangs around, quietly minding its own business, has been discovered outside the Milky Way galaxy.
According to the team, this is the first time we have been able to definitively detect and identify an inactive black hole that is outside of our own galaxy.
Although a similar discovery was announced last year, evidence of her true identity has left some doubts. place for doubt. This new discovery, according to the authors, is a good bet.
It should be recognized that the object is not too far from the Milky Way, it is located inside a satellite galaxy called the Large Magellanic Cloud. But this discovery could help us find more such black holes in the future and has implications for our understanding of black hole formation.
The team behind the report is clearly excited, and not least. due to their skeptical reputation for questioning previous discoveries of sleeping black holes.
“This is the first time our team has come together to report the discovery of a black hole rather than dismiss it,” said astronomer Tomer Shenar. University of Amsterdam in the Netherlands.
“We found a ‘needle in a haystack’.”
Black holes are cunning creatures. Their extreme density creates an extremely strong gravitational field, which means that even light traveling through a vacuum – the fastest light possible in the universe – cannot reach space velocity.
This means that they are shrouded in darkness, emitting no light that we can detect. The exception is when they are actively “feeding” or accumulating material. This is a erratic process that creates a telltale X-ray signature in the vicinity of a black hole.
Inactive or at rest black holes are more or less invisible. But annoying gravity can give it away… if you can look. If a stellar-mass black hole is in a binary system with another star, the orbital motion of a companion orbiting what appears to be empty space could indicate the presence of the black hole.
However, not all dark masses are black holes. Other astronomers have been deceived before, the most famous example being a black hole advertised as being the closest to Earth ever found. The culprit could be a dim little companion whose light is indistinguishable, meaning that neither option can be left unaddressed.
Shenar and members of his team, including astronomer Karim El-Badri of the Harvard and Smithsonian Research Center.
The astrophysicist and Julia Bodensteiner of the European Southern Observatory were among those who painstakingly refuted such findings. But this does not mean that they believe that such black holes do not exist; the evidence must simply be irrefutable.
“For more than two years, we have been looking for such binary systems of black holes,” explained Bodensteiner.
Spotlight The target of their search was the Tarantula Nebula in the Large Magellanic Cloud, a stellar nursery where extremely massive young stars can be found. The researchers studied about 1,000 of these young massive stars in detail, looking for the characteristic double orbital wobble.
When any two objects orbit each other, they do so around a common center of gravity, called their barycenter.
For a system like the Earth and the Sun, the barycenter would be close enough to the center of the Sun that it would be difficult to see the star move around it from a great distance. If the Earth were more massive, the Sun’s rotation around the barycenter would be much easier to detect.
We can detect this oscillatory motion or radial speed in the spectrum of light from an object as it stretches into longer (redder) wavelengths moving away from us and shrinks into shorter (bluer) wavelengths moving towards us.
The team looked for these spectral shifts in their sample and succeeded with a massive blue-white O-type. a star 25 times heavier than the Sun, located at a distance of about 160,000 light years.
When they calculated the mass of the object that could have caused the observed wobble, they found that the mass of the companion was about 9 times that of the Sun. At that mass, the event horizon of a black hole would be only 27 kilometers (17 miles) across.
Yet she was invisible. The upper mass limit for neutron stars is about 2.3 times that of the Sun, so this rules them out. Other stars in their sample that oscillated were eliminated using the team’s methods to detect light from faint companion stars and simulate the light expected from a faint companion of observed mass.
None of the alternative explanations fit. observational data.
“When Tomer asked me to double-check his findings, I had my doubts,” El-Badri said. “But I couldn’t find a plausible explanation for the non-black hole data.”
A binary file called VFTS 243 may contain important information about how black holes form. Scientists believe that there are several scenarios. The first is a colossal supernova in which an unstable star erupts, ejecting its outer material into space, and the core collapses into a black hole born of fire and fury.
The second is a direct collapse, in which a dying star, no longer supported by the external pressure created by atomic fusion, simply…collapses into itself, not with a crash, but with a quiet ker-flump.
“The star that formed the black hole in VFTS 243 appears to have completely collapsed, with no sign of a previous explosion,” Shenar said. “Evidence for this ‘outright collapse’ scenario is recent, but our study provides perhaps one of the most direct indications. This has huge implications for the origin of black hole mergers in space.”
Although, of course, having scrutinized so many other black hole discoveries, the team is now inviting other astronomers to study their findings. Fair.
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