ANALYZING THE DRESSLER CATALOG USING THE POINTWISE DIMENSION

摘要

In this paper I explore the application of the pointwise dimension as a large-scale structure descriptor to the Dressler catalog. This technique lias been particularly illuminating in the study of correlations between morphology and environment, and its application to the familiar problem of morphology- environment relationships offers new insights. An examination of the 55 clusters in the Dressler catalog (each cluster containing between ~40 and ~250 galaxies with morphology information) finds that for the combined Dressler data, Komolgorov-Smirnov tests show that the environments of the early-type galaxies are statistically different to the 99 level from the environments of the late-type galaxies. This result is in agreement with the general concept of a morphology-density relationship. Furthermore, 14 individual clusters were examined; these clusters had velocities determined for many of the individual galaxies. These velocities were used solely to determine cluster membership. Each of these 14 clusters showed very few of the statistical differences between morphological environments that characterized the combined Dressler catalog. This contradiction found between the combined sample (for which fore- ground members were not removed) and these individual clusters (for which contamination was seriously reduced) suggests that the morphology-density relationship is not applicable to at least one-quarter of the clusters from which the result was credited in the first place (and in which the relationship should therefore be most evident), and it is therefore not as fundament