Spitzer Helps Locate Primitive Quasars -
Up to now, primitive black holes, which occupy the cores of active galaxies and were around as far back as the early days of the universe, only existed in astronomer’s models. Researchers have now found two such gravitational monsters, however, which revealed themselves as brightly glowing quasars. Their light originates from a time when the universe was barely one billion years old - and we can see them now exactly as they appeared 12.7 billion years ago (Nature, March 18, 2010).
A quasar is the central region of a galaxy that contains an active black hole. The black hole is surrounded in turn by a brightly glowing disk of gas and dust. Matter swirls towards the black hole and emits radiation before disappearing into it. As a result, these accretion disks are among the brightest objects in the entire universe. Quasars shine so brightly that it is possible to obtain information about their physical characteristics from enormous distances.
It takes around 13 billion years for the light from the most distant known quasars to reach us. Therefore, when we observe these objects we go back 13 billion years into the past. Based on this, the scientists would expect to discover comparatively primitive precursors of the modern quasars, which are only in the process of formation in this period in the immediate aftermath of the Big Bang. However, observations made in 2003 revealed that the most distant quasars do not differ significantly from their contemporary counterparts, which are located closer to Earth.
A team of astronomers working with Linhua Jiang from the University of Arizona, which includes researchers from the Max Planck Institute for Astronomy in Heidelberg and the Max Planck Institute for Extraterrestrial Physics in Garching, has observed for the first time objects that appear to be very primitive early forms of modern quasars. The team used NASA’s Spitzer Space Telescope, which can see infrared light. The characteristic radiation of hot dust can be identified on the basis of observations in this spectral range - and this kind of dust is a typical component of modern quasars.