NASA’s Swift satellite and Japan’s Suzaku X-ray observatory claimed to have discovered a new class of active galactic nuclei (AGN).
AGN is distinguished from common galaxies as class, most luminous in the universe, such as quasars, blazars, and Seyfert galaxies, mostly powered by supermassive black holes, often emitting energy that equals energy of billion of stars from a region no larger than our solar system.
Evidence with respect to the new type of AGN began over the past two years and with the help of Burst Alert Telescope (BAT) Jack Tueller, of NASA’s Goddard Space Flight Center, found nearby AGNs that were previously missed because their visible and ultraviolet light was smothered by gas and dust.
These two newly discovered AGNs, targeted by Japan’s Suzaku, were found to be residing in the galaxies ESO 005-g004 and ESO297-G018, which are about 80 million and 350 million light years from Earth, respectively.
This discovery will help scientists to explain why the previous X-ray AGN surveys missed these two AGNs as Suzaku was expected to cover broader range of X-ray energies than BAT, however, in spite of this advantage, it detected very low or medium range energies.
As believed previously, AGNs are surrounded by donut-shaped ring of materials, which partially obscures our view of the black hole. Team member Richard Mushotzky thinks that a shell of obscuring material, which made it difficult for us to locate, surrounds these AGNs.
We can see visible light from other types of AGN because there is scattered light. But in these two galaxies, all the light coming from the nucleus is totally blocked, says Mushotzky.
The astronomers are of the opinion that 20 percent of X-ray radiations constitute these objects based on the previous observations. However, these observations, based upon Chandra observatory, were unable to identify the nature of all these sources.
Discovery of these new AGNs is an important step towards understanding the evolution of universe as black holes are thought to play important role in this process.
‘You can’t understand the universe without understanding giant black holes and what they’re doing. To complete our understanding we must have an unbiased sample’, says Tueller.
Image Credit: SPACE
Via: PhyOrg
