Astronomers detect hot gas bubble around the Milky Way’s supermassive black hole

·2-min read
This shows a still image of the supermassive black hole Sagittarius A*, as seen by the Event Horizon Collaboration (EHT Collaboration/ESO/M Kornmesse)
This shows a still image of the supermassive black hole Sagittarius A*, as seen by the Event Horizon Collaboration (EHT Collaboration/ESO/M Kornmesse)

Astronomers have detected a hot gas bubble swirling around the Milky Way’s supermassive black hole.

They say the finding helps to us to better understand the mysterious environment of the black hole called Sagittarius A*.

The observations suggest the gas bubble is on an orbit similar in size to that of Mercury, but making the loop in little over an hour.

We think we're looking at a hot bubble of gas zipping around Sagittarius A* on an orbit similar in size to that of the planet Mercury, but making a full loop in just around 70 minutes

Dr Maciek Wielgus, Max Planck Institute

Maciek Wielgus of the Max Planck Institute for Radio Astronomy in Bonn, Germany, said: “We think we’re looking at a hot bubble of gas zipping around Sagittarius A* on an orbit similar in size to that of the planet Mercury, but making a full loop in just around 70 minutes.

“This requires a mind-blowing velocity of about 30% of the speed of light.”

The observations were made using the Atacama Large Millimetre/submillimetre Array (ALMA), a radio telescope co-owned by the European Southern Observatory (ESO) – during a campaign by the Event Horizon Telescope (EHT) Collaboration to image black holes.

Some of the observations were done shortly after a burst or flare of X-ray energy was emitted from the centre of our galaxy.

These kinds of flares, previously observed with X-ray and infrared telescopes, are thought to be associated with so-called hot spots, hot gas bubbles that orbit very fast and close to the black hole.

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

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

Researchers say the findings seem to support the long-standing idea that the flares originate from magnetic interactions in the very hot gas orbiting very close to Sagittarius A*.

Team used the new observations together with theoretical models to learn more about the formation of the hot spot and the environment it is embedded in, including the magnetic field around the black hole.

They suggest their research provides stronger constraints on the shape of this magnetic field than previous observations, helping astronomers uncover the nature of our black hole and its surroundings.

The findings are published in the Astronomy & Astrophysics journal.