2 years ago
With some help from NASA’s Chandra X-ray Observatory, astrophysicists are one step closer to figuring out how and why supermassive black holes form.
An x-ray image recently taken by the Chandra Observatory contains the highest concentration of supermassive black holes seen to date, and an international team of astronomers is already studying the image for clues about how black holes form and grow over time.
There has been much speculation over the growth of black holes shortly after the Big Bang (roughly one billion years ago, give or take), but no definitive conclusions have been drawn as of yet. One reason for that is their location.
“It can be very difficult to detect black holes in the early Universe, because they are so far away and they only produce radiation if they’re actively pulling in matter,” said Bin Luo, an astronomer at Nanjing University in China. One common source of frustration for researchers like him is that the black hole “seeds” that provide clues about their massive growth can only be found in pretty remote parts of the Universe. Consequently, they’re really hard to observe.
This incredibly deep Chandra x-ray image is a game-changer, though. “By staring long enough with Chandra, we can find and study large numbers of growing black holes, some of which appear not long after the Big Bang,” Luo said. The image he and his team have been studying is the deepest of its kind ever obtained, and is the result of 11.5 weeks of observation time.
From this image, and other related data, the researchers are finding that black holes resulting from the Big Bang grew in bursts, rather than slowly, over long periods of time, because their “seeds” were much heavier than previously thought. Evidence also shows that their masses were about 10,000 to 100,000 times larger than our Sun to start.
Furthermore, the researchers detected x-ray emissions from massive, distant galaxies, which likely came from stars collapsing into black holes. This too is an exciting development.
“By detecting x-rays from such distant galaxies, we’re learning more about the formation and evolution of stellar-mass and supermassive black holes,” said Penn State’s Fabio Vito, a postdoctoral scholar in astronomy and astrophysics. “We’re looking back to times when black holes were in crucial phases of growth, similar to hungry infants and adolescents.”