Abstract: During the first part of its mission the X-ray observatory ROSAT conducted the first All Sky Survey with an X-ray telescope. Of the order of 50,000 X-ray sources were detected in the survey data. Presumably thousands of clusters of galaxies are among the detected sources and several hundred clusters have already been identified. First results suggest that the final catalogue of X-ray selected clusters of galaxies will probably be quite different from the present optical catalogues. This catalogue will provide the basis for very interesting studies of the luminosity function, cluster evolution, and the spatial distribution of clusters in the Universe. In the ongoing pointed observation program of ROSAT individual clusters of galaxies are studied. Due to the higher spatial resolution and sensitivity compared to previous instruments a more detailed investigation of the dynamical state, the mass distribution, and the gas content of clusters will be possible. This is especially interesting with respect to the problem of the “missing mass” and the evolution of the intracluster medium. First results from both observing programs are presented in this paper. The cosmological relevance of the observations and the propects for the further ROSAT mission are discussed.
Publication Year: 1992
Publication Date: 1992-01-01
Language: en
Type: book-chapter
Indexed In: ['crossref']
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Cited By Count: 3
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