Nearby Galaxy's Giant Black Hole Is Real, 'Shadow' Image Confirms

"A familiar shadow looms in a fresh image of the heart of the nearby galaxy M87," reports Science magazine. "It confirms that the galaxy harbors a gravitational sinkhole so powerful that light cannot escape, one generated by a black hole 6.5 billion times the mass of the Sun."But compared with a previous image from the network of radio dishes called the Event Horizon Telescope (EHT), the new one reveals a subtle shift in the bright ring surrounding the shadow, which could provide clues to how gases churn around the black hole. "We can see that shift now," says team member Sera Markoff of the University of Amsterdam. "We can start to use that." The new detail has also whetted astronomers' desire for a proposed expansion of the EHT, which would deliver even sharper images of distant black holes. The new picture, published this week in Astronomy & Astrophysics, comes from data collected 1 year after the observing campaign that led to the first-ever picture of a black hole, revealed in 2019 and named as Science's Breakthrough of the Year. The dark center of the image is the same size as in the original image, confirming that the image depicts physical reality and is not an artifact. "It tells us it wasn't a fluke," says Martin Hardcastle, an astrophysicist at the University of Hertfordshire who was not involved in the study. The black hole's mass would not have grown appreciably in 1 year, so the comparison also supports the idea that a black hole's size is determined by its mass alone. In the new image, however, the brightest part of a ring surrounding the black hole has shifted counterclockwise by about 30 degrees. That could be because of random churning in the disk of material that swirls around the black hole's equator. It could also be associated with fluctuations in one of the jets launched from the black hole's poles - a sign that the jet isn't aligned with the black hole's spin axis, but precesses around it like a wobbling top. That would be "kind of exciting," Markoff says. "The only way to know is to keep taking pictures...." [T]he team wants to add more telescopes to the network, which would further sharpen its images and enable it to see black holes in more distant galaxies. Thanks to Slashdot reader sciencehabit for sharing the news.

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