NASA spots millions of new quasars, a thousand galactic Hot DOGs
The WISE space-based infrared survey telescope has completed two surveys of the sky in the infrared, revealing millions of new supermassive (and ravenous) black holes called quasars. And we weren't exactly looking for Hot DOGs out there, but we found a bunch of 'em anyway.
WISE specializes in observing in the deep infrared part of the spectrum, looking for sources of light that we'd associate with heat energy, sort of like looking at the universe through a pair of night-vision goggles. And just like night-vision goggles, WISE can see straight through some things (like dust clouds) that block visible light. This makes it particularly good at spotting very energetic objects that are very far away, and JPL has just announced that it's found a few new candidates for supermassive black holes called quasars.
By a few, we mean approximately 2.5 million. JPL is calling it a "bonanza" of quasars, so you know they're excited. A quasar is more of a place than a thing: it's a region of space surrounding a supermassive black hole where a bunch of stuff is in the process of being consumed, emitting massive amounts of energy as it does so. In the context of a quasar, a massive amount of energy is something equivalent to about two trillion suns, or about the output of your average galaxy. To sustain this, the black hole at the center of the quasar is eating the equivalent of some 600 Earths every minute. A full two-thirds of the quasars found by WISE had never been seen before.
Also announced today was the detection of galactic Hot DOGs, which are an acronym (as you may have guessed) for hot, dust-obscured galaxies. Hot DOGs are notable in that they host active supermassive black holes at their cores, and they're the among the most luminous objects in the entire universe, pumping out as much energy as 100 trillion suns (!) or about 1,000 times more energy than the entire Milky Way galaxy (!!). WISE has spotted about a thousand of these, and it's thought that they're "cataclysmically forming galaxies" undergoing a rare stage of galactic evolution, powered by supermassive black holes of their own.
Below, we have a gallery for you with images and captions from NASA's press release, some of which have been edited for space.
Via NASA
All images and captions below courtesy NASA.
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The entire sky as mapped by WISE at infrared wavelengths is shown here, with an artist's concept of the WISE satellite superimposed.
With its all-sky infrared survey, NASA's Wide-field Infrared Survey Explorer, or WISE, has identified millions of quasar candidates. Quasars are supermassive black holes with masses millions to billions times greater than our sun. The black holes "feed" off surrounding gas and dust, pulling the material onto them. As the material falls in on the black hole, it becomes extremely hot and extremely bright. This image zooms in on one small region of the WISE sky, covering an area about three times larger than the moon. The WISE quasar candidates are highlighted with yellow circles.
This artist's concept illustrates a quasar, or feeding black hole, similar to APM 08279+5255, where astronomers discovered huge amounts of water vapor. Gas and dust likely form a torus around the central black hole, with clouds of charged gas above and below. X-rays emerge from the very central region, while thermal infrared radiation is emitted by dust throughout most of the torus. While this figure shows the quasar's torus approximately edge-on, the torus around APM 08279+5255 is likely positioned face-on from our point of view.
NASA's Wide-field Infrared Survey Explorer (WISE) has identified about 1,000 extremely obscured objects over the sky, as marked by the magenta symbols. These hot dust-obscured galaxies, or "hot DOGs," are turning out to be among the most luminous, or intrinsically bright objects known, in some cases putting out over 1,000 times more energy than our Milky Way galaxy.
This image zooms in on the region around the first "hot DOG" (red object in magenta circle), discovered by NASA's Wide-field Infrared Survey Explorer, or WISE. Hot DOGs are hot dust-obscured galaxies. Follow-up observations with the W.M. Keck Observatory on Mauna Kea, Hawaii, show this source is over 10 billion light-years away. It puts out at least 37 trillion times as much energy as the sun. WISE has identified 1,000 similar candidate objects over the entire sky (magenta dots). These extremely dusty, brilliant objects are much more rare than the millions of active supermassive black holes also found by WISE (yellow circles).
This zoomed-in view of a portion of the all-sky survey from NASA's Wide-field Infrared Survey Explorer shows a collection of quasar candidates. The larger yellow circles show WISE quasar candidates; the smaller blue-green circles show quasars found in the previous visible-light Sloan Digital Sky Survey. WISE finds three times as many quasar candidates with a comparable brightness. Thanks to WISE's infrared vision, it picks up previously known bright quasars as well as large numbers of hidden, dusty quasars. The circular inset images, obtained with NASA's Hubble Space Telescope, show how the new WISE quasars differ from the quasars identified in visible light. Quasars selected in visible light look like stars, as shown in the lower right inset; the cross is a diffraction pattern caused by the bright point source of light.
This plot illustrates the new population of "hot DOGs" found by WISE. The purple band represents the range of brightness observed for the extremely dusty objects, which can block our view. The red line shows the brightness profile, or spectral energy distribution, of a proto-typical infrared luminous galaxy. The small images near the top show more familiar objects at a range of temperatures from 70 Kelvin, or minus 330 degrees Fahrenheit, for liquid nitrogen, to 1,500 Kelvin, or 2,240 degrees Fahrenheit, for lava. The energy from hotter objects peaks at shorter wavelengths. The extreme WISE objects represented by the purple band are much brighter — and peak at much shorter, or hotter, wavelengths — than the typical infrared luminous galaxy, hence their nickname: hot dust-obscured galaxies, or Hot DOGs.
This image is a portion of the all-sky survey from NASA's Wide-field Infrared Survey Explorer, or WISE. It highlights the first of about 1,000 "hot DOGs" found by the mission (magenta circle). Yellow circles are active supermassive black holes found by WISE, which are much more common. The panels at right show the "Hot DOG" as seen in the four individual infrared bands obtained by WISE. These images are at wavelengths from 5 to 30 times redder than what our eyes can see, with the shortest wavelengths at top, and longest at bottom.These objects are so dusty that not only their visible light but also their shorter-wavelength infrared light is blocked, as evident by their apparent absence in the top two panels. Less than one in 100,000 WISE sources are similarly prominent only in the two longer-wavelength WISE infrared bands.
