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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, 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 that observers first thought was a galaxy. However, spectrographic studies done at Kitt Peak National Observatory 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 in Greenbelt, Md., and John Stocke of the University of Arizona at Tucson made the picture.
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Publication:Science News
Date:Jun 29, 1985
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