For 14 months a NASA satellite has circled the Earth 15 times a day, taking infrared snapshots of the universe every 11 seconds which have captured a plethora of previously unknown supermassive black holes from the very early universe. Scientists hope to use the information provided by NASA’s WISE survey to discover more about the evolution of a galaxy with the supermassive black hole at its core.
The black holes have not been detected before due to obscuring layers of dust, leading the new cosmic entities to be dubbed “hot DOGs.” Dust-Obscured Galaxies, the oldest of which are 10 to 11 billion light years away, are not visible to optical equipment not only because light from some 2 billion years after the universe began is only now reaching us but because the dust layers surrounding these galaxies tends to capture the light. NASA’s Wide-field Infrared Survey Explorer was able to see the hot DOGs using infrared equipment to detect the vast amounts of heat the supermassive black holes put out.
The WISE survey has found around 2.5 million active black holes and identified about 1000 candidates for dust-obscured galaxies. So why are NASA scientists so excited about the 100 confirmed DOGs? Peter Eisenhardt, project manager of WISE at NASA’s jet propulsion laboratory, said “It changes our concept of how brilliant and powerful galaxies can be.” It’s predicted that the dust-obscured galaxies, with a supermassive black hole at their heart, can put out as much as 100 trillion times as much light as our own sun. NASA scientists also believe the new discovery could provide valuable information on the evolution of galaxies; they believe the dust-obscured galaxies may represent a transitional link between disk-shaped galaxies, such as the Milky Way, and elliptical galaxies.
It is the complex relationship between the growth of supermassive black holes and their surrounding galaxies that astronomers most hope to learn about with the new data. The supermassive black holes are believed to grow through collisions with other galaxies which creates stars for the black holes to feed on in the case of these monsters that can be the equivalent of 300 suns. The violent collisions also throw up the cosmic dust that obscure the galaxies during so-called feeding periods.
Daniel Stern, of the Jet Propulsion Lab and lead author of the black hole study, is the project scientist for NuSTAR which will focus high-energy cosmic x-rays to learn more about the most energetic objects in our universe. The Nuclear Spectroscopic Telescope Array produces images with 100 times the sensitivity and 10 times the resolution of older technology operating on the same wave length. The census, whose prime mission will last 2 years, will center on black holes both inside and out of our own Milky Way galaxy to better our understanding of how these supermassive black holes behave and evolve.
While our own Milky Way galaxy is nearly as old as the universe itself we don’t quite understand everything about its formation. The data from supermassive black holes and dust-obscured galaxies are arriving from 11 billion light years away, when the universe was only a fraction of its current age. NASA’s WISE and NuSTAR project may reveal our galaxy’s origins. Peter Eisenhardt went so far as to say these findings “may push the boundaries of what we think is physically possible.”