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LOOK: Wits scientists in team that unveiled the supermassive black hole in the centre of our Milky Way

The first image of Sagittarius A*, a supermassive black hole in the center of the Milky Way Galaxy. (Image: EHT Collaboration)

The first image of Sagittarius A*, a supermassive black hole in the center of the Milky Way Galaxy. (Image: EHT Collaboration)

Published May 13, 2022


Two scientists from the University of the Witwatersrand (Wits) were among the research team that unveiled the first image of the supermassive black hole at the centre of the Milky Way galaxy.

The image of the cosmic body, known as Sagittarius A*, provides the first direct visual evidence of its existence.

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Produced by a global research team called the Event Horizon Telescope (EHT) Collaboration, the image was taken using observations from a worldwide network of radio telescopes.

Wits post-doctoral fellow, Dr Iniyan Natarajan, and Professor Roger Deane, Director of the Wits Centre for Astrophysics, were the only two researchers from Africa in an international team of over 300 people from 80 institutes.

The image of the black hole took over five years to produce, using supercomputers to combine and analyse their data.

Natarajan and Deane contributed by providing precision measurements of the black hole ring size using a suite of algorithms.

The duo also assisted in developing the software suite used to simulate realistic EHT datasets. These were critical to robustly compare the observations with predictions from Einstein’s General Theory of Relativity.

Deane said Southern Africa holds a distinct geographic advantage to host new EHT telescopes.

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“Especially if we wish to make movies of the Milky Way’s supermassive black hole, which passes directly above us in the southern sky,” he said.

The black hole itself is not visible, but it is identified by the glowing gas surrounding it. The image captures light bent by the powerful gravity of the black hole, which is four million times more massive than our Sun.

EHT Project Scientist from the Institute of Astronomy and Astrophysics, Academia Sinica, Taipei, Geoffrey Bower, said the size of the ring coincided with predictions from Einstein’s Theory of General Relativity.

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“These unprecedented observations have greatly improved our understanding of what happens at the very centre of our galaxy, and offer new insights on how these giant black holes interact with their surroundings,” he said.