by Astronomers have spotted a supermassive black hole in Earth’s cosmic backyard blasting jets of matter at sub-light speeds. These outflows tell the story of a battle for supremacy between magnetism and gravity.
The discovery could help scientists better understand how black holes create matter and eject powerful jets that extend far beyond their host galaxies.
The team of astronomers made observations of the heart of the radio galaxy 3C 84, also known as Perseus A, a region powered by a feeding supermassive black hole, using the Event Horizon Telescope (EHT). The EHT, a global array of linked radio dishes, produced the first images of a black hole ever seen by mankind.
Perseus A, a strong source of radio waves, corresponds to the center of the active galaxy NGC 1275, which is itself the central galaxy in the Perseus cluster, located 230 million light years from Earth. This sounds like an amazing distance, but it makes the newly observed object one of the closest supermassive black holes to our planet.
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“The radio galaxy 3C 84 is particularly interesting because of the challenges in accurately detecting and measuring the polarization of light near its black hole,” study team member Jae-Young Kim, associate professor of astrophysics at Kyungpook National University in South Korea, said in a statement. “The EHT’s exceptional ability to penetrate the dense interstellar gas is a breakthrough to precisely observe the neighborhood of black holes.”
Magnetism vs. gravity: Which force won?
The new Perseus A observations are not the first time the EHT has probed the powerful magnetism or gravity of a supermassive black hole, two of the four fundamental forces of the universe.
After the telescope first imaged the supermassive black hole at the heart of the galaxy Messier 87 (M87), it also imaged the polarization of light around this black hole, which is as massive as 6.5 billion suns.
This work revealed details of the polarized magnetic fields around M87’s central black hole. And, in the new research, the EHT observed polarization around the Perseus A black hole, indicating a well-ordered magnetic field in its immediate vicinity.
These magnetic fields show their power by getting the massive gravity of the black hole of the radio galaxy 3C 84, which is estimated to be 40 million times the mass of the sun, to launch jets at high speeds.
“Besides providing the first images of black holes, the EHT is ideally suited to observe astrophysical plasma jets and their interaction with strong magnetic fields,” said team leader Georgios Filippos Paraschos, of the Max Planck Institute for Radio Astronomy (MPIfR) in Germany. “Our new results provide new evidence that an ordered magnetic field spreads throughout the heated gas covering the black hole.”
As the matter falls towards the black hole, it forms an “accretion disk” around the strongly magnetized object. As this disc spins, the magnetic field lines within it twist, becoming rigid, preventing the effective release of magnetic energy.
EHT observations of the rapidly rotating supermassive black hole Perseus A and its surrounding “magnetically captured disk” suggest that the speed at which a black hole rotates may be related to its ability to launch jets.
This means that even though these jets show magnetism winning out over gravity, they could be getting help in the form of “external interference” from angular momentum. A deeper investigation and application of Einstein’s 1915 theory of gravity, general relativity, may help determine if this is the case.
“Why are black holes so good at producing powerful jets? This is one of the most interesting questions in astrophysics,” said MPIfR researcher Maciek Wielgus. “We expect that general relativistic effects that occur just above the black hole’s event horizon may hold the key to answering this question. Such high-resolution observations are paving the way toward observational verification.”
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The EHT was able to make its deep observations of this black hole and its jets using a technique called very long-baseline interferometry (VLBI), which allows an image to be created by pooling signals from multiple observations telescope on the same object. . The EHT is made up of an array of individual telescopes around the globe that come together to form a single instrument on Earth.
“We are very happy, because these results are a significant step towards understanding galaxies like 3C 84,” said Anton Zensus, director of the MPIfR and head of its Radio Astronomy/VLBI research department. “Together with our international partners, we are trying to improve the capabilities of the Event Horizon Telescope to enable a more detailed view of jet formation around black holes.”
The team’s research was published online Today (February 1) in the journal Astronomy and Astrophysics.
