Astronomers capture first image of supermassive black hole’s glowing ring

By Mark Waghorn via SWNS

A supermassive black hole's glowing, fluffy ring has been captured by astronomers for the first time.

It connects high-energy fire-hose-like jets of gas at close to the speed of light.

The awe-inspiring photos will help physicists understand the effect of the plasma on its surroundings.

An international team combined observations from the Global Millimetre VLBI Array (GMVA), ALMA (Atacama Large Millimetre/submillimetre Array) in Chile, the Greenland Telescope (GLT) and the EHT (Event Horizon Telescope).

It enabled them to peel back the layers of the black hole - first identified six years ago - to form a more 'zoomed-out' view.

Kazunori Akiyama, a research scientist at MIT who developed the software, said: "This is the first image where we are able to pin down where the ring is - relative to the powerful jet escaping out of the central black hole.

"Now we can start to address questions such as how particles are accelerated and heated and many other mysteries around the black hole more deeply."

The supermassive black hole lies 55 million light-years away in a galaxy named M87.

It made headlines around the world when it became the first to be pictured in 2019. It closely resembled theoretical predictions of what they should look like.

There was a golden ring of material racing around the outer edge - the light-trapping surface called the event horizon.

Now this 'curtain' has been drawn back to reveal a thicker, fluffier one that is 50 percent larger.

It's a reflection of GMVA's resolution which was tuned to pick up more of the super-hot, glowing gas surrounding the black hole.

Part of it consists of gas from a surrounding accretion disk - a swirling pancake of white-hot electrons being heated to hundreds of billions of Kelvin as the plasma streams into the black hole.

The images also reveal plasma blasting out from the central ring - a bright beam of matter called a relativistic jet.

The scientists tracked these emissions back toward the black hole and observed the base is linked to the central ring.

They used a technique known as VLBI (very-long-baseline interferometry). When a radio signal passes by Earth, such as from a black hole’s plasma emissions, radio dishes around the world can pick it up.

Scientists can then determine the time at which each dish registers the signal, and the distance between dishes, and combine this information in a way that the same signal is seen by every dish simultaneously as one very large, planet-scale telescope.

When each radio telescope is dialed to a specific frequency, the array as a whole can focus in on a particular feature of the radio signal.

The Event Horizon Telescope's network was tuned to 1.3 millimeters - a resolution equivalent to seeing a grain of rice in California from Massachusetts.

At this resolution, astronomers could see past most of the plasma surrounding M87 and image the thinnest ring, thereby accentuating the black hole's shadow.

In contrast, the GMVA network works at a slightly lower resolution of 3 millimeters. With this focus, the array could resolve a pumpkin seed, rather than a grain of rice.

The network itself consists of about a dozen radio telescopes scattered around the United States and Europe, mostly located along the east-west axis of the Earth.

To make a truly planet-sized telescope able to capture a far-off radio signal from M87, astronomers had to expand the array's 'eye' to the north and south.

ALMA is an array of 66 radio dishes located in the Atacama Desert. They were synchronized to work as one powerful and essential part of the GMVA network.

Dr. Lynn Matthews, of MIT, said: "Having these two telescopes as part of the global array resulted in a boost in angular resolution by a factor of four in the north-south direction.

"This greatly improves the level of detail we can see. And in this case, a consequence was a dramatic leap in our understanding of the physics operating near the black hole at the centre of the M87 galaxy."

Coordinating the telescopes resulted in pictures that reveal more plasma surrounding the black hole - in the form of a larger, fluffier ring.

The astronomers could also spot plasma trailing up and out from the central glowing ring.

Akiyama said: "The exciting thing is, we still see a shadow feature of the black hole, but we also start to see a more extended jet.

"For plasma to emit light at this wavelength, it has to be very heated, such that each particle in the plasma travels almost at the speed of light.

"So particles are accelerated to relativistic speeds. And we see that in the case of M87, this jet is extending and traveling across a really large scale."

The astronomers hope to pin down more properties of the black hole's plasma, such as its temperature profile and composition.

For this, they plan to tune the EHT and GMVA to new resolutions. By observing M87 at multiple wavelengths, they can then construct a layered picture, and a more detailed understanding of black holes and the jets they generate.

Geoffrey Crews, a research scientist at MIT, said: "If something major happens in the world, you might tune in to both AM and FM to assemble a 'complete picture' of the event.

"This is no different. You might think of the EHT M87 image being made in FM, and this result coming from AM. Both tell a story, and together it is a better story."

Supermassive black holes lie at the centre of every galaxy - including the Milky Way. They may even create them.

The study is published in the journal Nature.