August 30, 2012
NASA’s Wide-field Infrared Survey Explorer (WISE) is revealing energetic, previously unobserved supermassive black holes, including a new mega-powerful class of objects that appear to have influenced the transformation of galaxies, astronomers reported Aug. 29.
Observations with a range of space- and ground-based observatories over the past decade have revealed the presence of supermassive black holes at the center of every galaxy.
WISE, launched in late 2009 to conduct all-sky surveys with unprecedented sensitivity at infrared wavelengths, detected 2.5 million actively feeding supermassive black holes stretching back to distances of 10 billion light-years — nearly 70% of them previously undetected because they were obscured by dust and gas. Among the discoveries are an estimated 1,000 dust-obscurred galaxies, or DOGS, that are considered the brightest star systems ever found.
These extremely energetic objects generate 100 trillion times as much light as the Sun, thus the new nickname “hot Dog,” said Peter Eisenhardt, WISE project scientist.
The tremendous energy comes from a rich diet of dust and gas falling into the central black holes with masses billions of times that of the Sun.
Theorists believe these supermassive objects may form as spiral galaxies, like the Milky Way, merge. The merger creates a more chaotic second kind of star system, an elliptical galaxy. Ellipticals are populated predominantly by older stars, explained Rachel Somerville, a Rutgers University astrophysicist who joined the presentation.
“We may be seeing a new, rare phase in the evolution of galaxies,” said Jingwen Wu, an astronomer from NASA’s Jet Propulsion Laboratory, who led a followup study of the WISE observations.
“These provide targets that we will be able to study in tremendous detail with the new James Webb Space Telescope,” Somerville says. “That will help us pin down an explanation for the process that is actually driving the growth of these black holes — whether it’s actually these mergers and interactions events or some other process.”