Low Dispersion Spectra of Galaxies. I. The Coma and Virgo Clusters

摘要

Low dispersion objective-prism spectra (approximately 10,000 A/mm) have been obtained of galaxies in the Coma and Virgo Clusters. Composite color indices were derived from the spectra, which when combined wiht magnitudes obtained from the Catalogue of Galaxies and of Clusters of Galaxies, (Zwicky et al.) allowed color magnitude diagrams for the clusters to be drawn. The differences between the diagrams for different clusters indicate that the method will prove useful in the study of the color distribution within clusters of galaxies, as well as in the identification of the bluest and reddest galaxies which migh warrant further study at a higher dispersion. (Author)