Black Holes Abound - In The Millions
August 29, 2012

Millions Of Black Holes Discovered By NASA’s WISE Mission

Lee Rannals for - Your Universe Online

Millions of black holes have been discovered, as well as extreme galaxies called hot DOGs using NASA's Wide-field Infrared Survey Explorer (WISE) mission.

The telescope has helped reveal millions of dusty black hole candidates throughout the universe, and about 1,000 dustier objects that are thought to be the brightest galaxies ever found called dust-obscured galaxies, or hot DOGs.

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

The telescope scanned the sky twice in infrared light to complete its survey in early 2011, capturing millions of images in the sky.

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

The latest findings can help astronomers have a better understanding of how galaxies and the giant black holes at their centers grow and evolve together.

The giant black hole at the center of the Milky Way galaxy has four million times the mass of our sun, and has gone through periodic feeding frenzies where material falls towards the black hole, heats up, and then irradiates its surroundings.

Astronomers were able to identify about 2.5 million actively feeding supermassive black holes across the full sky using WISE. About two-thirds of these objects have never been detected before because dust blocks their visible light, but the NASA telescope is able to see the monster black holes through infrared light.

"We've got the black holes cornered," Daniel Stern of NASA's Jet Propulsion Laboratory, Pasadena, Calif., and lead author of the WISE black hole study, said in a press release "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."

The hot DOGs found can pour out more than 100 trillion times as much light as our own sun. They are so dusty, they appear only in the longest wavelengths of infrared light captured by WISE.

NASA's Spitzer Space Telescope did a follow up on discoveries, helping astronomers see these DOGs are spitting out new stars.

"These dusty, cataclysmically forming galaxies are so rare WISE had to scan the entire sky to find them," Peter Eisenhardt, lead author of the paper on the first of these bright, dusty galaxies, and project scientist for WISE at JPL, said in a press release. "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.'"

Over 100 of these objects have been confirmed using the W.M. Keck Observatory on Mauna Kea, Hawaii, as well as the Gemini Observatory in Chile.

The astronomers' observations have revealed that these galaxies are more than twice as hot as other infrared-bright galaxies. One theory is that 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," Jingwen Wu of JPL, lead author of the study on the submillimeter observations, said in the release.

Three papers about the findings were published in the Astrophysical Journal.

The three technical journal articles, including PDFs, can be found at, and .