Distortions in the Properties of Galaxy Clusters - Part One - Inhomogeneity of the Catalogs
B. I. Fesenko · 1979
The data in the Zwicky and Abell galaxy catalogs are inhomogeneous because the observing conditions vary from plate to plate. A simple statistical method is developed for analyzing this inhomogeneity by comparing the fluctuations in the count of clusters within a plate and the analogous fluctuations in the count from one plate to the next. Examination of samples drawn from the two catalogs shows that inhomogeneity of the data contributes significantly to the dispersion in the counts of clusters. In previous research, neglect of this fact and inadequate allowance for irregular absorption has led to the erroneous inference that many clusters belong to superclusters of galaxies. There is evidence for appreciable inhomogeneity in the magnitude estimates of Zwicky galaxies with m in the range 15/sup m/.4--15/sup m/.7. The problem of inhomogeneous data within a single plate is discussed briefly.