First image of black hole enhanced, revealing extreme magnetic fields

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

The supermassive black hole in the center of Messer 87, nicknamed M87 *, has slowly let go of his secrets as astrophysicists combed through the enormous amount of data generated by the EHT. A few more secrets were uncovered on Wednesday as members of the EHT collaboration reveal new images of the black hole in polarized light.

In a suite of new articles, the collaboration details groundbreaking new images, which provide critical information on the magnetic fields immediately surrounding the black hole and those further from the chaotic center of Messier 87. This is the first time that a team is able to measure polarization very close to the edge of a black hole.

“The recently published polarized images are essential to understanding how the magnetic field allows the black hole to ‘eat’ matter and launch powerful jets,” said Andrew Chael, astrophysicist at the Princeton University Center for Theoretical Science and member of the EHT collaboration.

But what exactly is polarization and why is it important?

Well the light is weird. It is made up of electric and magnetic fields, vibrating in all kinds of directions. Polarized light only vibrates in a direction. Most light is unpolarized when it leaves a star or the huge, glowing disc of gas and debris around a black hole, but its interactions with dust, plasma, and magnetic fields can cause it. polarize. The detection of the polarization then provides a signature of the environment around a black hole such as M87 *.

The first black hole image provided a sort of hazy Eye of Sauron, a ring of orange and yellow light around a black spot. The light emanates from a disc of debris and matter immediately surrounding the invisible black hole. Some of this material slides into the black hole, never to be seen again, but other material is thrown at right angles, deep into space in what is called a “cosmic jet”.

M87’s jet of material is ejected at almost the speed of light and spans nearly 5,000 light years in space. But how it forms remains a mystery.

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 repel the hot gas and help it resist the pull of gravity,” said Jason Dexter, astrophysicist at the University of Colorado Boulder and coordinator of EHT Theory Working Group. “Only gas that slides across the field can fly inward to the event horizon.”

The magnetic fields closest to the black hole can be so extreme that they project matter far from the edge and concentrate it in the enormous jet observed emanating from Messier 87.

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

A particular telescope that is part of the collaboration, the Atacama Large Millimeter / submillimeter Array (ALMA) in Chile, also provided an astonishing look at the black hole jet in polarized light, displaying 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 extremely bright beasts with jets pointing directly at Earth (known as “blazars “) were very strongly polarized, which the researchers hypothesize is probably because of the direction they are facing.

The first image of a black hole has impressed, but there are many more mysteries to be discovered. The EHT will provide new opportunities to study the regions closest to M87 * and Sgr A * as more observatories are added and the network is modernized.

“We expect future EHT observations to more accurately reveal the structure of the magnetic field around the black hole and tell us more about the physics of hot gases in this region,” said Jongho Park, an astrophysicist at the Institute of astronomy and astrophysics Academia Sinica of Taipei. and member of the EHT collaboration.