In 2019, the Event Horizon Telescope Collaboration delivered the first image of a black hole, revealing M87*—the supermassive object in the center of the M87 galaxy. The team has now used the lessons learned last year to analyze the archival data sets from 2009-2013, some of them not published before.
The analysis reveals the behavior of the black hole image across multiple years, indicating persistence of the crescent-like shadow feature, but also variation of its orientation—the crescent appears to be wobbling. The full results appeared today in The Astrophysical Journal.
An animation showing the consistency of the measured ring diameter and the uncertainties of the orientation measurement. Credit: M. Wielgus and the EHT Collaboration
The Event Horizon Telescope is not one singular telescope, but a global partnership of telescopes—including the UChicago-led South Pole Telescope—which performs synchronized observations using the technique of Very Long Baseline Interferometry. Together they form a virtual Earth-sized radio dish, providing a uniquely high image resolution.
“The Event Horizon Telescope is giving us a new tool to study black holes and gravity in ways that were never before possible,” said Bradford Benson, an associate professor of astronomy and astrophysics at UChicago. “As members of the South Pole Telescope (SPT) collaboration and the EHT network, we look forward to contributing to future studies—in particular on Sgr A*, the black hole at the center of the Milky Way galaxy, which we have a unique view of given SPT’s location at the geographical South Pole.”
“With the incredible angular resolution of the Event Horizon Telescope, we could observe a billiard game being played on the Moon and not lose track of the score!” said Maciek Wielgus, an astronomer at Center for Astrophysics | Harvard & Smithsonian, Black Hole Initiative Fellow, and lead author of the new paper.
“Last year we saw an image of the shadow of a black hole, consisting of a bright crescent formed by hot plasma swirling around M87*, and a dark central part, where we expect the event horizon of the black hole to be,” said Wielgus. “But those results were based only on observations performed throughout a one-week window in April 2017, which is far too short to see a lot of changes.”