Abstract
view Abstract Citations (13) References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Subclustering of Galaxies. Abell, G. O. ; Neyman, J. ; Scott, E. L. Abstract Extending the method introduced by Holmberg to study the hypothesis that large clusters of galaxies contain small subclusters, we have used the counts of Abell to estimate, indirectly, the frequency of subclusters, their spatial extent, and the average number of subcluster members. Seven clusters have been studied. The method used allows for the fact that a large cluster is concentrated towards its center. Circular rings are drawn about each galaxy in the central area of the cluster and, following Holmberg, the number of galaxies is counted in each ring about each galaxy. In addition, a dense square grid of points is projected on the photograph of the cluster and similar rings are constructed and counts of galaxies made in each ring about each grid point. Clearly, if there is subclustering the counts about galaxy centers will tend to be higher than the counts about point centers. However, the concentration of the cluster alone will produce some excess. Therefore we first estimate the structure of the central part of the cluster and, using this, estimate the structure of the subclusters. The table gives preliminary results for the existence of subclustering, the mean number of companions per galaxy, and the estimated standard deviation ~ of the distances of galaxies from their subcluster centers. Mean No. Abell Existence of of corn- a No. Cluster subclustering panions (kpc) Virgo slight 0.05 120 1656 Coma no 2199 Around 6166 exists 0.3 110 2151 Hercules some 0.1 120 151 HaufenA some 0.05 90 2065 CorBor no 665 exists 0.5 160 Publication: The Astronomical Journal Pub Date: 1964 DOI: 10.1086/109381 Bibcode: 1964AJ.....69Q.529A full text sources ADS |
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