A hot gas bubble is detected around the Milky Way’s supermassive black hole

Astronomers have detected a bubble of hot gas swirling around the Milky Way’s supermassive black hole at more than 200 million miles per hour.

It orbits Sagittarius A* at nearly one-third the speed of light in an orbit similar in size to the planet Mercurycompleting a full circle in just 70 minutes.

Experts say the discovery could help us better understand the enigmatic and dynamic environment of the huge void at the heart of our galaxy.

Lead author Dr Maciek Wielgus of the Max Planck Institute for Radio Astronomy in Germanysaid: “We believe it to be a hot bubble of gas circulating around Sagittarius A* in an orbit similar in size to the planet Mercury – but completing a full loop in just around 70 minutes. “

He added: “It requires mind-blowing speed of about 30% of the speed of light.”

Mysterious: Astronomers have detected a bubble of hot gas swirling around the Milky Way’s supermassive black hole at more than 200 million miles per hour. The ALMA radio telescope has spotted signs of a ‘hot spot’ orbiting Sagittarius A* (pictured), the black hole at the center of our galaxy

WHAT IS SAGITTARIUS A* AND HOW WAS IT Caught ON CAMERA?

Sagittarius A* – abbreviated as Sgr A*, which is pronounced “sadge-ay-star” – owes its name to its detection in the direction of the constellation of Sagittarius.

Its existence has been presumed since 1974, with the detection of an unusual radio source at the center of the galaxy.

In the 1990s, astronomers mapped the orbits of the brightest stars near the center of the Milky Way, confirming the presence of a supermassive compact object there – work that led to the 2020 Nobel Prize in Physics.

Although the presence of a black hole was considered the only plausible explanation, the new image provides the first direct visual evidence.

Because it is 27,000 light years from Earth, it appears in the sky the same size as a donut on the moon.

Capturing images of such a distant object required linking eight giant radio observatories across the planet to form a single virtual Earth-sized telescope called the EHT.

These included the 30-meter telescope at the Institute of Millimeter Radio Astronomy (IRAM) in Spain, the most sensitive single antenna in the EHT array.

The EHT looked at Sgr A* over multiple nights for several hours at a stretch – an idea similar to long exposure photography and the same process used to produce the first image of a black hole, published in 2019.

This black hole is called M87* because it is in the galaxy Messier 87.

An international team spotted the “hot spot” using the Atacama Large Millimeter/submillimeter Array (ALMA) radio telescope in the Chilean Andes.

Supermassive black holes are incredibly dense areas at the center of galaxies. They act as intense sources of gravity that suck dust and gas around them.

Sagittarius A*, located just 26,000 light-years from Earth, is one of the few black holes in the universe where we can actually observe the flow of matter nearby.

But because the area absorbs all the surrounding light, it’s incredibly hard to see, so scientists have spent decades looking for clues of black hole activity.

The observations were made by the European Southern Observatory (ESO) during a campaign of the Event Horizon Telescope (EHT) collaboration to image black holes.

In April 2017, eight existing radio telescopes were linked around the world, resulting in the first-ever image of Sagittarius A*.

Dr. Wielgus and colleagues used ALMA data recorded simultaneously with EHT observations of Sagittarius A*.

There were more clues to the nature of the black hole hidden in the ALMA measurements alone.

Coincidentally, some were made shortly after a burst or burst of X-ray energy was emitted from the center of the Milky Way and detected by NASA’s Chandra Space Telescope.

These types of flares, previously observed with X-ray and infrared telescopes, are thought to be associated with “hot spots” – bubbles of gas that orbit very quickly and close to the black hole.

Dr Wielgus said: ‘What is really new and interesting is that such flares have so far only been clearly present in X-ray and infrared observations of Sagittarius A*.

“Here we see for the first time a very strong indication that orbiting hotspots are also present in radio observations.”

Less than one percent of the matter initially under the black hole’s gravitational influence reaches the event horizon, or the point of no return, because much of it is ejected.

Therefore, the X-ray emission from matter is remarkably faint, like that of most giant black holes in galaxies in the near universe.

Co-author Jesse Vos, a PhD student at Radboud University, the Netherlands, said: “Perhaps these hotspots detected at infrared wavelengths are a manifestation of the same physical phenomenon.

“As infrared-emitting hotspots cool, they become visible at longer wavelengths, such as those observed by ALMA and the EHT.”

The flares were thought to originate from magnetic interactions in the extremely hot gas orbiting very close to the black hole. Research results support this idea.

Co-author Dr Monika Moscibrodzka, also from Radboud, said: ‘We are now finding strong evidence of a magnetic origin for these eruptions and our observations give us a clue to the geometry of the process.

“The new data is extremely useful in constructing a theoretical interpretation of these events.”

ALMA allows astronomers to study polarized radio emissions from Sagittarius A*, which can be used to uncover the black hole’s magnetic field.

An international team spotted the 'hotspot' using the Atacama Large Millimeter/submillimeter Array (ALMA) radio telescope in the Chilean Andes (pictured)

An international team spotted the ‘hotspot’ using the Atacama Large Millimeter/submillimeter Array (ALMA) radio telescope in the Chilean Andes (pictured)

The data combined with theoretical models shed light on the formation of the hotspot and the environment in which it is embedded, including the magnetic field.

Stronger constraints on the shape than previous observations help uncover the nature of our black hole and its surroundings.

Scans from ALMA and ESO’s Very Large Telescope (VLT) GRAVITY instrument, which observes in the infrared, suggest the eruption originated from a cluster of gas.

It swirls around the black hole at about 30% the speed of light clockwise across the sky – the hotspot’s orbit being almost head-on.

Co-author Dr Ivan Marti-Vidal from the University of Valencia said: ‘In the future we should be able to track hotspots across frequencies using coordinated observations at multiple lengths. wave with GRAVITY and ALMA.

“The success of such an endeavor would be a real milestone for our understanding of the physics of flares in the galactic center.”

This wide-field view in visible light shows the rich star clouds of the constellation Sagittarius (The Archer) heading towards the center of our Milky Way galaxy

This wide-field view in visible light shows the rich star clouds of the constellation Sagittarius (The Archer) heading towards the center of our Milky Way galaxy

The team also hopes to be able to directly observe gas clusters in orbit with the EHT, probe ever closer to the black hole and learn more about it.

Dr Wielgus added: “Hopefully one day we’ll be comfortable saying we ‘know’ what’s going on in Sagittarius A*.”

The formation of black holes is still poorly understood. Astronomers believe it happens when a large cloud of gas up to 100,000 times larger than the sun collapses.

Many of these “seeds” then coalesce to form much larger supermassive black holes, which sit at the center of all known massive galaxies.

Alternatively, a supermassive black hole seed could originate from a giant star, about 100 times the mass of the sun, which eventually turns into a black hole after running out of fuel and collapsing.

When these giant stars die, they also go into a “supernova,” a huge explosion that blasts material from the star’s outer layers into deep space.

The new study has been published in the journal Astronomy & Astrophysics.

WHAT IS ALMA?

Deep in the Chilean desert, the Atacama Large Millimeter Array, or ALMA, is located in one of the driest places on earth.

At an altitude of 16,400 feet, about half the cruising height of a jumbo jet and nearly four times the height of Ben Nevis, workers had to haul oxygen tanks to complete its construction.

Commissioned in March 2013, it is the most powerful ground-based telescope in the world.

It’s also the highest on the planet and, at nearly £1 billion ($1.2 billion), one of the most expensive of its kind.

Deep in the Chilean desert, the Atacama Large Millimeter Array, or ALMA, is located in one of the driest places on earth.  Turned on in March 2013, it is the most powerful ground-based telescope in the world

Deep in the Chilean desert, the Atacama Large Millimeter Array, or ALMA, is located in one of the driest places on earth. Turned on in March 2013, it is the most powerful ground-based telescope in the world