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Paper: The evolution of galaxies and galaxy clusters associated with quasars
Volume: 10, Evolution of the Universe of Galaxies: Edwin Hubble Centennial Symposium
Page: 322
Authors: Yee, H. K. C.
Abstract: Results from a number of systematic imaging surveys of fields around quasars are described and summarized. From these surveys, correlations between the environments of quasars and quasar properties can be derived and properties of associated galaxies and galaxy clusters at moderately high redshifts can be measured. Quasars in general are found to be situated in regions of enhanced galaxy density. Specifically, radio-loud quasars are found in environments significantly richer than those of radio-quiet quasars. However, there is some preliminary evidence that some radio-quiet quasars are located at the edges of rich clusters. A significant fraction of radio-loud quasars are located at or near the centers of rich clusters of galaxies. Furthermore, compared to quasars found in poorer environments, quasars situated at the centers of rich clusters have undergone a much more rapid luminosity evolution in the redshift range between 0.6 and 0.4. This may be a direct consequence of the evolution of the physical conditions in the centers of rich clusters. Preliminary results from the study of clusters associated with quasars show that they may systematically have properties which are believed to be favorable to the existence of quasar activity. The luminosity function (LF) of the associated galaxies at z of about 0.6 is found to be brighter than the local LF by about 0.9 +/-0.3 mag, which can be interpreted as luminosity evolution in early-type galaxies in moderately rich environments.
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