Five supermassive black holes have been discovered by astronomers for the first time, adding weight to the theory that there are millions yet to be found.
The supermassive black holes were not previously detected as they are hidden from direct view by swathes of dust and gas, but thanks to NASA’s recently launched Nuclear Spectroscopic Telescope Array (NuSTAR), Durham University astronomers were able to identify the black holes through the high-energy x-rays they emit.
“For a long time we have known about supermassive black holes that are not obscured by dust and gas, but we suspected that many more were hidden from our view,” said study lead author George Lansbury, a postgraduate student at Durham University’s Centre for Extragalactic Astronomy.
“Thanks to NuSTAR for the first time we have been able to clearly see these hidden monsters that are predicted to be there, but have previously been elusive because of their ‘buried’ state.”
NuSTAR, the orbiting high-energy x-ray telescope, was only launched in 2012, before which such a discovery could not have been made.
As a result, the astronomers believe there are far more supermassive black holes left to be discovered, with the number thought to be in the millions.
“Although we have only detected five of these hidden supermassive black holes, when we extrapolate our results across the whole Universe then the predicted numbers are huge and in agreement with what we would expect to see,” said Lansbury.
The five detected supermassive black holes were found following the selection of nine candidate sites, where astronomers thought activity at the centre of galaxies could be attributed to such a black hole.
In the five where they did find supermassive black holes, they were not surprised to discover they were hidden by dust as gas, but were surprised at how bright and active they were; the black holes were guzzling the materials surrounding them, emitting large amounts of radiation and making them brighter than expected.
The research is being presented today at the Royal Astronomical Society’s National Astronomy Meeting, in Llandudno, Wales, and will be published in The Astrophysical Journal later this year.
While undoubtedly an exciting discovery for astrophysicists, the findings are a major success story for NASA’s young telescope array, and suggest NuSTAR could produce far more supermassive black hole findings in the future.
“High-energy X-rays are more penetrating than low-energy X-rays, so we can see deeper into the gas burying the black holes,” said Daniel Stern, NuSTAR project scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California.
“NuSTAR allows us to see how big the hidden monsters are and is helping us learn why only some black holes appear obscured.”