By Katie McQuaid
Associate Director, Communications and Marketing
After sharing the world’s first images of a black hole with the world in 2019, the Event Horizon Telescope (EHT) team has not slowed down. Last year, the global collaborative effort of over 400 researchers shared photos of a different black hole, M87* that gave us an even more detailed view of what a black hole looks like. That image, which is actually many images put together from telescopes all over the world, was created from data collected two years earlier.
The EHT team recently released a follow-up to the 2024 paper reporting on the results from the 2018 observations of M87* entitled “The persistent shadow of the supermassive black hole of M87”. The paper, published in Astronomy & Astrophysics, included additional images of M87* and discusses what the new images mean compared to what was released last year. While this paper isn’t sharing new information about M87*, it does something even more important: it confirms the researchers' interpretations of the imagery.
This means that what they believed they saw in M87* and how the data was interpreted was correct the first time around. While the important parts are constant, that doesn’t mean that M87* isn’t changing, because it is.
Observed and theoretical images of M87*. The left panels display EHT images of M87* from the 2018 and 2017 observation campaigns. The middle panels show example images from a general relativistic magnetohydrodynamic (GRMHD) simulation at two different times. The right panels present the same simulation snapshots, blurred to match the EHT's observational resolution.
“We started to see changes, and that's exactly what we would have expected,” said Avery Broderick, professor at the University of Waterloo and Research Associate Faculty at Perimeter Institute, who leads the Waterloo team processing the EHT data.
“M87*’s event horizon is about a light-day across, so its accretion disk should present a new version of itself on a timescale of just a few days. All our simulated models give us some sense of how much it should be varying, and this is an important confirmation. This paper is about understanding what these images mean in the context of our best numerical simulations.”
Waterloo’s contribution to the EHT is wide-ranging and significant, according to Broderick. “There is no other institution with a contribution larger than ours,” he said. “A lot of the 2018 analysis was led by our colleagues at the Academia Sinica Institute of Astronomy and Astrophysics (ASIAA) in Taiwan.”
“Interestingly, the people who led both the paper that came out last January and this one came through Waterloo as students and postdoctoral researchers. We’re not only doing a vast amount of work on the project in Waterloo, we’re also training the next generation of leaders in EHT.”
While Waterloo researchers lead the way in uncovering the mysteries of a black hole, the analysis released today represents a global collaboration of talent, technology, and effort, showcasing the remarkable innovations that become achievable through collective effort.
The study, "The persistent shadow of the supermassive black hole of M87," is published in Astronomy & Astrophysics.