NASA's WISE Survey Uncovers Millions of Black Holes

With its all-sky infrared survey, NASA's Wide-field Infrared Survey Explorer, or WISE, has identified millions of quasar candidates. 

Image credit: NASA/JPL-Caltech/UCLA

NASA's Wide-field Infrared Survey Explorer (WISE) mission has led to a bonanza of newfound supermassive black holes and extreme galaxies called hot DOGs, or dust-obscured galaxies.

Images from the telescope have revealed millions of dusty black hole candidates across the universe and about 1,000 even dustier objects thought to be among the brightest galaxies ever found.

These powerful galaxies, which burn brightly with infrared light, are nicknamed hot DOGs.

"WISE has exposed a menagerie of hidden objects," said Hashima Hasan, WISE program scientist at NASA Headquarters in Washington.

"We've found an asteroid dancing ahead of Earth in its orbit, the coldest star-like orbs known and now, supermassive black holes and galaxies hiding behind cloaks of dust."

WISE scanned the whole sky twice in infrared light, completing its survey in early 2011. Like night-vision goggles probing the dark, the telescope captured millions of images of the sky.

All the data from the mission have been released publicly, allowing astronomers to dig in and make new discoveries.

The latest findings are helping astronomers better understand how galaxies and the behemoth black holes at their centers grow and evolve together.

For example, the giant black hole at the center of our Milky Way galaxy, called Sagittarius A, has 4 million times the mass of our sun and has gone through periodic feeding frenzies where material falls towards the black hole, heats up and irradiates its surroundings.

Bigger central black holes, up to a billion times the mass of our sun, may even shut down star formation in galaxies.

In one study, astronomers used WISE to identify about 2.5 million actively feeding supermassive black holes across the full sky, stretching back to distances more than 10 billion light-years away.

About two-thirds of these objects never had been detected before because dust blocks their visible light. WISE easily sees these monsters because their powerful, accreting black holes warm the dust, causing it to glow in infrared light.

"We've got the black holes cornered," said Daniel Stern of NASA's Jet Propulsion Laboratory, Pasadena, Calif., lead author of the WISE black hole study and project scientist for another NASA black-hole mission, the Nuclear Spectroscopic Telescope Array (NuSTAR).

"WISE is finding them across the full sky, while NuSTAR is giving us an entirely new look at their high-energy X-ray light and learning what makes them tick."