The first image of a black hole is updated, revealing extreme magnetic fields


Artist’s impression of the extreme environment at the center of the Messier 87 galaxy. A huge cosmic jet emerges from the central black hole.

ESO / M. Kornmesser

When the Event Horizon Telescope captured the first image of a black hole At the center of the Messier 87 galaxy, about 53 million light years from Earth, astronomers and scientists were delighted. The breakthrough snap had unlocked a powerful new way to study the giant cosmic beasts and put some of the most interesting astrophysical theories to the test.

The supermassive black hole at the center of Messer 87, designated M87 *, has little by little he has revealed his secrets as astrophysicists have reviewed the enormous amount of data generated by the EHT. On Wednesday, a few more secrets were unearthed when members of the EHT Collaboration revealed new images of the black hole in polarized light.

In a series of new articles, the collaboration details groundbreaking new images, providing critical information about the magnetic fields immediately surrounding the black hole and those furthest from the chaotic center of Messier 87. It is the first time that a team has been able to measure the polarization near the edge of a black hole.

“The recently released polarized images are key to understanding how the magnetic field allows the black hole to ‘eat’ matter and launch powerful jets,” said Andrew Chael, an astrophysicist at the Princeton University Center for Theoretical Sciences and a member of the EHT Collaboration. .

But what exactly is polarization and why does it matter?

Well, light is weird. It is made up of electric and magnetic fields that vibrate in all kinds of directions. Polarized light only vibrates in one address. Most light is unpolarized when it exits a star or the huge, bright disk of gas and debris around a black hole, but its interactions with dust, plasma, and magnetic fields can cause it to polarize. Detection of polarization provides a signature of the environment around a black hole like M87 *.

The first image of a black hole provided a kind of blurry Eye of Sauron, a ring of orange and yellow light around a black point. The light emanates from a disk of debris and material that immediately surrounds the invisible black hole. Some of this matter slides into the black hole, never to be seen again, but other material is thrown at right angles, deep into space in what is known as a “cosmic jet.”

M87’s jet of matter is ejected almost at the speed of light and stretches nearly 5,000 light-years into space. But how it is formed remains a mystery.

old and new

The first image of the black hole (left) and the new image, in polarized light (right).

EHT collaboration

The new observations provide a potential explanation.

“The observations suggest that the magnetic fields at the edge of the black hole are strong enough to push back the hot gas and help it resist the pull of gravity,” according to Jason Dexter, an astrophysicist at the University of Colorado Boulder and coordinator of the the EHT Theory. Workgroup. “Only gas that slides through the field can spiral toward the event horizon.”

The magnetic fields closest to the black hole can be so extreme that they shoot matter from the edge and focus it into the huge jet that is observed emanating from Messier 87.

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This is the jet emanating from the center of Messier 87. The yellow lines in the image indicate the magnetic fields present in the jet, which extends about 6,000 light-years into space.

ALMA (ESO / NAOJ / NRAO), Goddi et al.

The Event Horizon Telescope is not a single telescope, but a series of eight ground-based telescopes located around the world. It is a “virtual telescope”, as large as Earth, that captures the light that escapes around M87 *, providing the kind of resolution necessary to resolve these features, even though it is millions of light years away.

One particular telescope that is part of the collaboration, the Atacama Large Millimeter / submillimeter Array (ALMA) in Chile, also provided an impressive view of the black hole jet in polarized light, showing the magnetic field lines (right).

He also observed Sgr A *, the black hole at the center of the Milky Way, and a dozen other supermassive black holes, finding that extremely bright beasts with jets pointing directly at Earth (known as “blazars”) were very strongly polarized. . what the researchers hypothesize is likely because of the direction in which they are looking.

The first image of a black hole captivated, but there are many more mysteries to discover. The EHT will provide more opportunities to study the regions closer to M87 * and Sgr A * as more observatories are added and the network improves.

“We hope that future EHT observations will more accurately reveal the structure of the magnetic field around the black hole and tell us more about the physics of hot gas in this region,” said Jongho Park, an astrophysicist at Academia Sinica’s Institute of Astronomy and Astrophysics. Taipei. and member of the EHT collaboration.

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