Washington: Scientists have discovered a group of 'quiet' quasars that evolved slowly, with the help of the Gran Telescopio Canarias (GTC) telescope.
The telescope has enabled comparison, for the first time, of the local quasars with moderate luminosity with similar ones at much greater distances.
The tremendous light-gathering power of the GTC telescope, has recently enabled Jack W. Sulentic and his team at the Institute of Astrophysics of Andalusia (IAA-CSIC) to obtain for the first time spectroscopic data from distant, low luminosity quasars similar to typical nearby ones. Data reliable enough to establish essential parameters such as chemical composition, mass of the central black hole or rate at which it absorbs matter.
Sulentic has said that they have been able to confirm that, indeed, apart from the highly energetic and rapidly evolving quasars, there had been another population that evolved slowly called 'quiet' quasars.
The local quasars would present a higher proportion of heavy elements such as aluminium, iron or magnesium, than the distant relatives, which most likely reflected enrichment by the birth and death of successive generations of stars.
Aeons ago, the universe had been different: mergers of galaxies were common and gigantic black holes with masses equivalent to billions of times that of the Sun formed in their nuclei. As they captured the surrounding gas, the black holes would emit energy known as quasars, these very distant and tremendously high energy objects have local relatives with much lower energy.
Quasars have appeared to evolve with distance: the farther away one gets, the brighter they appeared. The gigantic quasars had been evolving very quickly, most of them already extinct, coexisted with a 'quiet' population that evolved at a much slower rhythm but with the present technological limitations the scientists were unable to research.
