The first photograph of a black hole has become a little clearer after years of analysis and with the help of a pair of Maunakea telescopes.
In 2019, the Event Horizon Telescope project — a network of eight radio telescopes around the world that includes the James Clerk Maxwell Telescope and the Submillimeter Array on Maunakea — made history by capturing the first image of a black hole.
The same project today released a second picture of the same black hole with more visible detail. Where the first image was of a blurry red ring, the new image reveals a swirl pattern that shows for the first time the structure of the intense magnetic field distortions around the black hole, said Jessica Dempsey, deputy director of the East Asian Observatory and JCMT.
“We’re finally seeing something that we’ve hypothesized for a long time,” Dempsey said. “It’s exciting for use to really get to drill down into what these magnetic fields are doing.”
The black hole is designated M87* — after the M87 galaxy it sits in the center of — but was given the name Powehi through the University of Hawaii’s College of Hawaiian Language. That name, derived from the Hawaiian creation chant Kumulipo, means “the adorned fathomless dark creation.”
The new image of Powehi is technically the same image as the one released in 2019. Dempsey said additional work has been done on the same data set, using the Event Horizon telescopes to view the object in polarized light.
Dempsey said the process is similar in principle to how polarized sunglasses can filter out bright lights and glare. Polarization allowed astronomers to trace the lines of the magnetic field surrounding Powehi.
That field is the cause of the swirl in the new image, Dempsey said. The magnetic field is coalescing around Powehi, but also funnels some of the matter drawn toward the supermassive object into enormous jets that are ejected from the object’s axes.
“Only a tiny amount of the hypothetical models we had before match what we’re seeing now,” Dempsey said, explaining that the new discovery gives more understanding about how magnetic fields are influenced by supermassive objects like Powehi or the black hole in the center of our own galaxy.
“What’s really exciting is that now we get to find out how it changes over time.”
Powehi differs from Sagittarius A* — the black hole at the center of the Milky Way Galaxy — in a few key ways that make it easier to image. Powehi is more massive than our black hole, but Sagittarius A* also spins far faster than Powehi, meaning it is much harder to image, in the same way that a photo of a runner comes out blurry, Dempsey said.
However, thanks to the Event Horizon Telescope project’s success with Powehi, Dempsey said an image — or images — of Sagittarius A* could be forthcoming soon.
Email Michael Brestovansky at mbrestovansky@hawaiitribune-herald.com.
