The “black hole police” discover the first dormant black hole outside the Milky Way, and it’s just 160,000 light-years from Earth

Image of the Tarantula Nebula, about 160,000 light-years away, showing a cosmic landscape of star clusters, glowing gas clouds, and scattered remnants of supernova explosions. EFE/ESO Photo: EFE

Stellar-mass black holes form when massive stars reach the end of their lives and collapse under their own gravity.

An international team of astronomers, known as the “black hole police” for their work challenging findings of these space elements, has discovered a new stellar-mass black hole in the Large Magellanic Cloud, a neighboring galaxy to the Milky Way.

The lead author of the study published today by Nature Astronomy, Tomer Shenar, points out that this is the first time that this team “has come together to publicize the discovery of a black hole, rather than refute it.”

“We identified a needle in a haystack,” says Shenar, who began the study at the KU Leuven center in Belgium and is now a Marie-Curie fellow at the University of Amsterdam in the Netherlands.

Although other similar candidates for black holes have been proposed, the scientific team says that this is the first “dormant” stellar-mass black hole to be unequivocally detected outside our galaxy.

Stellar-mass black holes form when massive stars reach the end of their lives and collapse under their own gravity.

In a binary system, made up of two stars revolving around each other, this process leaves an orbiting black hole with a luminous companion star.

The black hole is “dormant” if it is not emitting high levels of X-ray radiation, which is how these space elements are normally detected.

“It’s amazing that we hardly know about these dormant black holes, given how common the scientific community assumes they are,” says co-author Pablo Marchant of KU Leuven.

An international team of astronomers, known as the “black hole police” for their work challenging findings of these space elements, has discovered a new stellar-mass black hole in the Large Magellanic Cloud, a neighboring galaxy to the Milky Way.

The lead author of the study published today by Nature Astronomy, Tomer Shenar, points out that this is the first time that this team “has come together to publicize the discovery of a black hole, rather than refute it.”

“We identified a needle in a haystack,” says Shenar, who began the study at the KU Leuven center in Belgium and is now a Marie-Curie fellow at the University of Amsterdam in the Netherlands.

Although other similar candidates for black holes have been proposed, the scientific team says that this is the first “dormant” stellar-mass black hole to be unequivocally detected outside our galaxy.

Stellar-mass black holes form when massive stars reach the end of their lives and collapse under their own gravity.

In a binary system, made up of two stars revolving around each other, this process leaves an orbiting black hole with a luminous companion star.

The black hole is “dormant” if it is not emitting high levels of X-ray radiation, which is how these space elements are normally detected.

“It’s amazing that we hardly know about these dormant black holes, given how common the scientific community assumes they are,” says co-author Pablo Marchant of KU Leuven.

The newly found black hole is at least nine times the mass of our Sun and orbits a hot blue star that weighs twenty-five times the mass of the Sun.

Dormant black holes are particularly difficult to detect, since they don’t interact much with their surroundings.

“For more than two years, we have been looking for these kinds of binary black hole systems,” said co-author Julia Bodensteiner, a researcher at the European Southern Observatory (ESO) in Germany.

To find this black hole, dubbed VFTS 243, the team surveyed nearly a thousand massive stars in the Tarantula Nebula region of the Large Magellanic Cloud, looking for ones that might have black holes as companions.

An international team of astronomers, known as the “black hole police” for their work challenging findings of these space elements, has discovered a new stellar-mass black hole in the Large Magellanic Cloud, a neighboring galaxy to the Milky Way.

The lead author of the study published today by Nature Astronomy, Tomer Shenar, points out that this is the first time that this team “has come together to publicize the discovery of a black hole, rather than refute it.”

“We identified a needle in a haystack,” says Shenar, who began the study at the KU Leuven center in Belgium and is now a Marie-Curie fellow at the University of Amsterdam in the Netherlands.

Although other similar candidates for black holes have been proposed, the scientific team says that this is the first “dormant” stellar-mass black hole to be unequivocally detected outside our galaxy.

Stellar-mass black holes form when massive stars reach the end of their lives and collapse under their own gravity.

In a binary system, made up of two stars revolving around each other, this process leaves an orbiting black hole with a luminous companion star.

The black hole is “dormant” if it is not emitting high levels of X-ray radiation, which is how these space elements are normally detected.

“It’s amazing that we hardly know about these dormant black holes, given how common the scientific community assumes they are,” says co-author Pablo Marchant of KU Leuven.

The newly found black hole is at least nine times the mass of our Sun and orbits a hot blue star that weighs twenty-five times the mass of the Sun.

Dormant black holes are particularly difficult to detect, since they don’t interact much with their surroundings.

“For more than two years, we have been looking for these kinds of binary black hole systems,” said co-author Julia Bodensteiner, a researcher at the European Southern Observatory (ESO) in Germany.

To find this black hole, dubbed VFTS 243, the team surveyed nearly a thousand massive stars in the Tarantula Nebula region of the Large Magellanic Cloud, looking for ones that might have black holes as companions.

Identifying these companions as black holes is extremely difficult, as there are so many alternative possibilities.

“As a researcher who has refuted possible black holes in recent years, I was extremely skeptical of this discovery,” admits Shenar.

This skepticism was shared by co-author Kareem El-Badry of the Harvard & Smithsonian Center for Astrophysics in the United States, whom Shenar dubs “the black hole destroyer.”

“When Tomer asked me to review his findings, I had my doubts. But I couldn’t find a plausible explanation for the data that didn’t involve a black hole,” explains El-Badry.

An international team of astronomers, known as the “black hole police” for their work challenging findings of these space elements, has discovered a new stellar-mass black hole in the Large Magellanic Cloud, a neighboring galaxy to the Milky Way.

The lead author of the study published today by Nature Astronomy, Tomer Shenar, points out that this is the first time that this team “has come together to publicize the discovery of a black hole, rather than refute it.”

“We identified a needle in a haystack,” says Shenar, who began the study at the KU Leuven center in Belgium and is now a Marie-Curie fellow at the University of Amsterdam in the Netherlands.

Although other similar candidates for black holes have been proposed, the scientific team says that this is the first “dormant” stellar-mass black hole to be unequivocally detected outside our galaxy.

Stellar-mass black holes form when massive stars reach the end of their lives and collapse under their own gravity.

In a binary system, made up of two stars revolving around each other, this process leaves an orbiting black hole with a luminous companion star.

The black hole is “dormant” if it is not emitting high levels of X-ray radiation, which is how these space elements are normally detected.

“It’s amazing that we hardly know about these dormant black holes, given how common the scientific community assumes they are,” says co-author Pablo Marchant of KU Leuven.

The newly found black hole is at least nine times the mass of our Sun and orbits a hot blue star that weighs twenty-five times the mass of the Sun.

Dormant black holes are particularly difficult to detect, since they don’t interact much with their surroundings.

“For more than two years, we have been looking for these kinds of binary black hole systems,” said co-author Julia Bodensteiner, a researcher at the European Southern Observatory (ESO) in Germany.

To find this black hole, dubbed VFTS 243, the team surveyed nearly a thousand massive stars in the Tarantula Nebula region of the Large Magellanic Cloud, looking for ones that might have black holes as companions.

Identifying these companions as black holes is extremely difficult, as there are so many alternative possibilities.

“As a researcher who has refuted possible black holes in recent years, I was extremely skeptical of this discovery,” admits Shenar.

This skepticism was shared by co-author Kareem El-Badry of the Harvard & Smithsonian Center for Astrophysics in the United States, whom Shenar dubs “the black hole destroyer.”

“When Tomer asked me to review his findings, I had my doubts. But I couldn’t find a plausible explanation for the data that didn’t involve a black hole,” explains El-Badry.

Image of the Tarantula Nebula, about 160,000 light-years away, showing a cosmic landscape of star clusters, glowing gas clouds, and scattered remnants of supernova explosions. EFE/ESO Photo: EFE
The discovery also offers the team a unique insight into the processes that accompany the formation of black holes.

The astronomical community believes that a stellar-mass black hole forms as the core of a dying massive star collapses, but it remains unclear whether or not this process is accompanied by a powerful supernova explosion.

“The star that formed the black hole in VFTS 243 appears to have completely collapsed, with no signs of an earlier explosion,” Shenar says.