WISE survey uncovers millions of black holes

The space telescope identified these actively feeding supermassive singularities across the whole sky and up to 10 billion light-years away.

By NASA Headquarters, Washington, D.C. — Published: August 30, 2012

With its all-sky infrared survey, NASA's Wide-field Infrared Survey Explorer (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 dust-obscured galaxies (hot DOGS).

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 that burn brightly with infrared light are nicknamed hot DOGs.

"WISE has exposed a menagerie of hidden objects," said Hashima Hasan from NASA Headquarters in Washington, D.C. "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 toward the black hole, heats up, and irradiates its surroundings. Bigger central black holes, up to a billion times the mass of our Sun, even may 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 black holes 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.

In two other WISE papers, researchers report finding what are among the brightest galaxies known, one of the main goals of the mission. So far, they have identified about 1,000 candidates.

These extreme objects can pour out more than 100 trillion times as much light as our Sun. They are so dusty, however, that they appear only in the longest wavelengths of infrared light captured by WISE. NASA's Spitzer Space Telescope followed up on the discoveries in more detail and helped show that, in addition to hosting supermassive black holes feverishly snacking on gas and dust, these DOGs are busy churning out new stars.

"These dusty, cataclysmically forming galaxies are so rare WISE had to scan the entire sky to find them," said Peter Eisenhardt, lead author of the paper on the first of these bright, dusty galaxies, and project scientist for WISE at the Jet Propulsion Laboratory in Pasadena, California (JPL). "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.'"

More than 100 of these objects, located about 10 billion light-years away, have been confirmed using the W.M. Keck Observatory on Mauna Kea, Hawaii, as well as the Gemini Observatory in Chile, Palomar's 200-inch Hale Telescope near San Diego, and the Multiple Mirror Telescope Observatory near Tucson, Arizona.

The WISE observations combined with data at even longer infrared wavelengths from Caltech's Submillimeter Observatory atop Mauna Kea, Hawaii, revealed that these extreme galaxies are more than twice as hot as other infrared-bright galaxies. One theory is their dust is being heated by an extremely powerful burst of activity from the supermassive black hole.

"We may be seeing a new, rare phase in the evolution of galaxies," said Jingwen Wu of JPL.

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WILLIAM STONE from CALIFORNIA said:

I wonder if black holes convert regular matter in dark matter, a change of states so to speak.

Submitted: 11/1/2012 9:27:05 AM (CST)

DANIEL GODWIN from ALABAMA said:

I suppose we can't see far enough back to witness it but I suspect that supermassive black holes and the matter that makes up a galaxy was created by super massive stars going mega-super-nova . Imagine an era in the very early universe when the first stars were all perhaps 1 billion times the mass of our sun . They formed from the origional matter from the big bang and were very short lived .

Submitted: 9/11/2012 1:16:04 PM (CST)

JOHN FAULKNER from SOUTH AFRICA said:

Could the gravitational pull of these millions of galaxies be sufficient to account for that presently ascribed to "dark Matter"?

Submitted: 9/10/2012 5:21:53 AM (CST)

ROBERT A MORSTADT from UTAH said:

An obvious question is how do these new galactic black holes affect the amount of missing ordinary matter in the universe? A few billion solar masses here and a few billion solar masses there might add up to some real astronomical missing mass. Perhaps, the amount of estimated ordinary mass in the universe might increase by some appreciable percentage.

Submitted: 9/8/2012 11:04:34 AM (CST)