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Analysis of unpublished data from observations of M87 * between 2009 and 2013 by scientists at the Event Horizon Telescope (EHT) has revealed that the growing shadow of the black hole wobbles and has rotated significantly during the last ten years of observation. Posted today in The Astrophysical Journaland directed by scientists from the Center for Astrophysics | Harvard & Smithsonian (CfA), the study focused on black hole morphology over time and was made possible by advances in analysis and understanding achieved as a result of EHT’s groundbreaking photo of a black hole in 2019. .
“EHT can detect changes in the morphology of M87 on timescales as short as a few days, but its general geometry must be constant over long timescales,” said Maciek Wielgus, CfA astronomer, Black Hole Initiative fellow ( BHI) and lead author on the paper. “In 2019, we saw the shadow of a black hole for the first time, but we only saw images observed during a one-week window, which is too short to see much change.”
Combining previous data from 2009-2013 with data before 2019 revealed that M87 * adheres to theoretical predictions. The shape of the black hole’s shadow has remained constant and its diameter remains in accordance with Einstein’s theory of general relativity for a 6.5 billion solar mass black hole. “In this study, we show that the general morphology, or the presence of an asymmetric ring, likely persists over time scales of several years,” said Kazu Akiyama, a scientist at MIT’s Haystack Observatory and a participant in the project. “This is an important confirmation of theoretical expectations, as consistency across multiple observing epochs gives us more confidence than ever about the nature of M87 * and the origin of the shadow.”
While the diameter of the crescent remained constant, the new data also shows that it was hiding a surprise: the ring is wobbling, and that means great news for scientists. For the first time, scientists will be able to glimpse the dynamic structure of the black hole’s accretion flow; Studying this region holds the key to understanding phenomena such as relativistic jet launches. “The morphology of a relativistic jet – low-density particle output and tremendously energetic fields – for example, is key to understanding interactions with the surrounding medium in a black hole’s host galaxy,” said Richard Anantua, a postdoc at the Center. of Astrophysics | Harvard & Smithsonian and BHI Fellow, adding that studying morphology weaves an important story about black holes and their hosts.
Gas that falls on a black hole heats up to billions of degrees, ionizes, and becomes turbulent in the presence of magnetic fields. This turbulence causes the appearance of the black hole to vary over time. “Because the flow of matter falling onto a black hole is turbulent, we can see that the ring wobbles over time,” Wielgus said. “The dynamics of this wobble will allow us to limit the flow of accretion.” Anantua added that it is important to restrict accretion flows because, “The accretion flow contains matter that is close enough to the black hole to allow us to observe the effects of strong gravity and, in some circumstances, allows us to test the predictions of relativity. general”. , as we have done in this study. “
In the current study, several years of data allow scientists to perceive the amount of variability in the appearance of the ring. “We actually see a lot of variation there, and not all theoretical accretion flow models allow for that much variability,” Wielgus said. “As we get more measurements in the future, we will be able to confidently place constraints on the models and discard some of them.”
The first data from the EHT collaboration were taken by a few telescopes and a few dozen people. CfA’s Submillimeter Array (SMA), a radio telescope located on Mauna Kea, Hawai’i, was among the small group that initiated the collaboration and captured the first data used for the current study. Simon Radford, SMA’s director of operations, said, “The Hawai’i telescopes pioneered this technique over the past decade and were crucial to the success of early EHT experiments,” adding that the combination of the technology , telescopes and location are the first useful and meaningful data.
Ten years later, the data has become an invaluable tool for understanding not just M87, but all black holes. “These early EHT experiments provide us with a trove of long-term observations that the current EHT, even with its remarkable imaging capabilities, cannot match,” said Shep Doeleman, founding director of EHT. “When we first measured the size of M87 in 2009, we couldn’t foresee that it would give us our first glimpse of black hole dynamics. If you want to see a black hole evolve over a decade, there is no substitute for having a decade of data. “. Wielgus added that continuous analysis of past observations, along with new observations “will lead to a better understanding of the dynamic properties of M87 and of black holes in general.”
The EHT and many of its key scientists are supported by funding from public entities, including the National Science Foundation and the Smithsonian Institution, and from private entities such as the John Templeton Foundation and the Gordon and Betty Moore Foundation.
