Quasar found in galaxy cluster.Quasar found in galaxy cluster For the first time in two decades of observing quasars, astrophysicists have found a quasar in the middle of a rich cluster of galaxies cluster of galaxies Gravitationally bound grouping of galaxies, numbering from the hundreds to the tens of thousands. Large clusters of galaxies often exhibit extensive X-ray emission from intergalactic gas heated to tens of millions of degrees. , a place where a lot of them have wanted to find one. The bright object (arrow) is the quasar 3C275.1. The others are galaxies. A popular theory of what quasars are says they are things that happen in the nuclei of galaxies, that is, they are particularly active galactic nuclei. Galaxies characteristically appear in clusters. If quasars are active galactic nuclei, objectors to the theory inquire, how come no quasar has ever been seen in a cluster of galaxies? This photograph shows one. The quasar in the picture is surrounded by a nebulosity neb·u·los·i·ty n. pl. neb·u·los·i·ties 1. The quality or condition of being nebulous. 2. Astronomy a. A nebula or a nebulalike object. b. A mass of material constituting a nebula. that observers first thought was a galaxy. However, spectrographic studies done at Kitt Peak National Observatory Kitt Peak National Observatory, astronomical observatory located southwest of Tucson, Ariz.; it was founded in 1958 under contract with the National Science Foundation and is administered by the Association of Universities for Research in Astronomy. in Tucson, Ariz., show that it is a gas cloud 300,000 light-years across. In the view of most theorists, the engine that produces a quasar's great energies centers on a black hole. This cloud could be matter drawn to the black hole out of the intergalactic medium of the cluster. The quasar and cluster are about 7 billion light-years away; the faintest objects in the picture are 10 million times fainter than the faintest stars visible to the naked eye. Paul Hintzen of NASA's Goddard Space Flight Center The Goddard Space Flight Center (GSFC) is a major NASA space research laboratory established on May 1, 1959 as NASA's first space flight center. GSFC employs approximately 10,000 civil servants and contractors, and is located approximately 6.5 miles northeast of Washington, D.C. in Greenbelt, Md., and John Stocke of the University of Arizona (body, education) University of Arizona - The University was founded in 1885 as a Land Grant institution with a three-fold mission of teaching, research and public service. at Tucson made the picture. |
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