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Faint Galaxies in the Coma and Corona Borealis Clusters

1971; Institute of Physics; Volume: 76; Linguagem: Inglês

10.1086/111102

1538-3881

Thomas W. Noonan,

Galaxies: Formation, Evolution, Phenomena

Studies of existing 200-inch plates of the Corona Borealis and Coma clusters give the following results. A large fraction of the detected galaxies are cluster galaxies. The fainter galaxies are less concentrated toward the cluster center than the brighter galaxies for the zone covered by the plates. The slope of the central logarithmic luminosity function is approximately 0.2 to 0.3 at the limit, and the slope of the logarithmic luminosity function for field galaxies is twice as large. The faint galaxies seem to offer no hope in solving the mass problem. Plates of Selected Area 57 show more field galaxies than those in the central region of the Coma cluster, an effect which could be due either to plate differences or to intergalactic absorption in the cluster. This study includes all faint galaxies, not merely the "dwarfs" of other investigators.