ANALYSIS OF GALAXY MORPHOLOGY AND EVOLUTION USING THE POINTWISE DIMENSION

In this paper we explore the application of the pointwise dimension (P D) analysis as a large-scale structure descriptor to the Third Referen ce Catalog of Bright Galaxies (RC3). This technique, which originated in the field of fractal geometry (Mandelbrot 1983) and found many appl ications in nonlinear dynamics, is particularly illuminating in the st udy of correlations between morphology and environment. To our knowled ge the technique is being applied for the first time to the study of g alaxy morphology and evolution. The PD is the slope of the curve repre senting the number of galaxies within some radius, determined separate ly for each galaxy in the catalog. Thus the distributions of PDs can b e compared for subsamples based on morphological type or luminosity. T he conclusions of this analysis of RC3 are as follows: (1) The PD eluc idates the tendency for early-type galaxies to cluster more than late- type galaxies; however, there is considerable overlap between these po pulations. (2) The PD statistic does not find a significant relationsh ip between luminosity and clustering in RC3, but it could be an effect ive diagnostic in larger two-dimensional catalogs. (3) The majority of galaxies in RC3 (excluding clusters) are spread out in space much lik e a random distribution. A population of objects that traces the distr ibution of galaxies, but avoids clusters, would have only small correl ations. It is worthwhile to pursue application of the PD to larger cat alogs with a wider range of luminosities.