This is the first image of Sagittarius A* (Sgr A*), the supermassive black hole at the center of our galaxy. The image of the Sgr A* black hole was captured by the Event Horizon Telescope and is an average of the various images.

Avery Broderick, a professor at the University of Waterloo and an associate faculty member at the Perimeter Institute for Theoretical Physics, is part of the international Event Horizon Telescope (EHT) collaboration that imaged the black hole, and he played a key role in image interpretation Data.

At this distance, imaging Sgr A* is like reading a newspaper in Los Angeles from a park bench in Manhattan.

The new image of Sgr A* will allow EHT scientists to compare black holes. Sgr A* is the second black hole captured by the EHT collaboration. In 2019, the team released a landmark image of a much larger and more distant black hole in the galaxy Messier 87 (M87*).

“Despite being 1,500 times smaller than M87*, the new images of Sgr A* look remarkably similar to those of M87*,” said Broderick, John Archibald Wheeler Professor of the Delaney Family at the Perimeter Institute. “Nobody knew for sure if huge black holes and relatively smaller holes would have much in common, but now we have two unique black holes to compare, so we can better understand how black holes of different sizes feed, how they grow and how they shape the galaxy around them.

Since Sgr A* is significantly smaller than M87*, light orbits the black hole in much less time than the larger black hole. This created a challenge for the researchers because over the observation period, Sgr A* experienced high variability in the data, which required completely new image analysis methods compared to those used. for M87*.

Broderick’s role in the EHT collaboration was at the forefront of image analysis work. His team has developed probability-based image modeling methods, called Bayesian images, to deal with this variability. Broderick’s method used probability to identify the features of this black hole and was able to conclude that Sgr A* had a bright ring and a dark center.

Images captured by EHT researchers show the dark central region from which light cannot escape. A fiery ring of superheated gas swirls around the black hole’s periphery, light barely escaping to begin its journey through 27,000 light-years toward the EHT telescopes.

At this distance, imaging Sgr A* is like reading a newspaper in Los Angeles from a park bench in Manhattan. The EHT collaboration has captured detailed images and data of the supermassive black hole by creating a network of precisely timed telescopes at sites spanning the globe; all focused on the powerful gravitational source at the heart of the Milky Way.

“The Event Horizon Telescope is a remarkable demonstration of the power of international scientific collaboration,” said Robert Myers, director of the Perimeter Institute. “Black holes were once just a theoretical playground for mathematical physicists. But the EHT collaboration has transformed black holes from theoretical ideas into objects of empirical observation and study. Perimeter Institute is proud to be part of this unprecedented scientific enterprise, which is just beginning.

Sgr A* is four million times more massive than our sun but had never been directly detected because black holes are literally black – they exert such gravitational force that not even light can escape their grip. Sgr A* is far too distant to affect us on Earth, but it has cataclysmic effects on its closest surroundings. Understanding the inner workings of black holes is crucial for testing, and perhaps revising, our best theory of gravity, Einstein’s general relativity.

“Now, more than ever, the world is looking to scientists to understand the world around us, and these groundbreaking images are inspiring a deeper fascination and curiosity about our universe,” said Bob Lemieux, dean of science at the University of Waterloo. “We are very proud of Avery’s leadership and dedication to the EHT collaboration and look forward to seeing the transformative work he continues to do at Waterloo.

More than 300 researchers from 80 institutes around the world called the Event Horizon Telescope Collaboration produced the image using observations from a global network of radio telescopes. The image of the Sgr A* black hole is an average of the various images that the EHT collaboration extracted from its 2017 observations.