The earliest known black hole in the universe has been spotted by the James Webb Space Telescope (JWST), and it could tell us about the origin of supermassive black holes that formed much later.
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| How do supermassive black holes, as seen in this illustration, get so big? Shutterstock/Sahara Prince |
Many galaxies have a supermassive black hole at their centre, but it is unclear exactly how they became so large. One possibility is they were formed by small black holes, created by early stars collapsing, joining together over time. Another suggestion is they are the result of vast amounts of gas in the early universe directly collapsing into a black hole, without ever being a star.
Now, Rebecca Larson at the University of Texas at Austin and her colleagues have identified the earliest example of a black hole yet, dating it to just 570 million years after the universe began, based on its distance from Earth. Its mass is 10 million times that of the sun, making it an intermediate black hole, by cosmic standards.
“This is really important uncharted territory of black hole formation and growth in the early universe,” says Larson. “We know where we have to get to, but we don’t quite know how we got there, and so we’re starting to now, for the first time, really fill in the gaps and put together a better picture of how these things formed.”
To identify the black hole, Larson and her team pointed JWST at a galaxy that the Hubble Space Telescope had previously identified as being the brightest known galaxy in this early part of the universe. However, Hubble had been unable to discern what was inside.
Using two cameras and two spectroscopes, JWST could pick out the different components that make up the light signal from the galaxy, which peak at certain points depending on the elements that produce them.
“One of them had a peak, but then it had a very fat, broad one underneath it, and I thought ‘That seems weird. I’ve not seen that before, what is this?’ And it turns out that’s from the black hole at the centre,” says Larson.
While we only have this one example of a black hole from so early in the universe, its mass seems to suggest it didn’t develop from a stellar mass black hole, says James Mullaney at the University of Sheffield, UK. “It is starting to rule out these stellar mass black holes as being viable sources, unless there’s some very rapid growth of these black holes in the very early universe.”
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