A Nasa space telescope has uncovered millions of previously unseen supermassive black holes, and around a thousand ‘extreme’ galaxies that can outshine our sun by a factor of 100 trillion.
The discoveries were previously obscured by layers of space dust, but Nasa’s Wide-Field Infrared Survey Explorer, known as WISE, can see in wavelengths correlated with heat, helping it to reveal some of the brightest objects in the known Universe.
WISE scanned the sky with infrared rays from December 2009 to February 2011, with scientists still poring over results that were first released in March.
In a news briefing yesterday, Daniel Stern of NASA's Jet Propulsion Laboratory in Pasadena, California, said: “WISE has found a bonanza of black holes in the universe.“
“We expected that there should be this large population of hidden quasars in the universe, but WISE can now identify them across the sky,” he added. “We think these quasars are really important for shaping how galaxies look today.”
WISE’s 2.5 million new black holes are roughly three times as many as have been revealed by comparable surveys in visible light.
These new black holes are not the usual small dense objects created by the collapse of dead stars, rather ‘supermassive’ quasars that feast on matter falling into them, creating some of the brightest objects in the Universe.
As well as the black holes, WISE also revealed around a thousand hot DOGs – the researchers’ nickname for blistering hot ‘dust-obscured galaxies’.
Although they appear very faint in WISE’s images, the galaxies are in fact incredibly bright, only appearing dulled by the layers of dust between them and the telescope.
Peter Eisenhardt, a WISE project scientist at the Jet Propulsion Laboratory said: “These dusty, cataclysmically forming galaxies are so rare WISE had to scan the entire sky to find them.”
“We are also seeing evidence that these record-setters may have formed their black holes before the bulk of their stars. The eggs may have come before the chickens,“ he added.
The data from the WISE mission is being made publicly available so scientists outside the team can carry out their own studies.Reuse content