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INTRODUCTION

There are no bigger assemblies of stars, gas, dust and dark matter known than galaxies or clusters of galaxies. Our galaxy, the Milky-way galaxy, is an average galaxy and yet it contains more than 1011 stars. The importance of studying galaxies can not be over emphasized because studying them is almost synonymous with studying the universe since they contain the information about its past, present and the future.

Human beings have been looking at galaxies for more than two hundred years with telescope aided eyes. The first photograph, in the visible range of the spectrum, came about 100 years ago but the proof of their existence, as external systems, did not come until 1924. In the 1950s the other windows of the electromagnetic spectrum started to give important information. In the last two decades the research has reached a significant level of maturity with galaxies routinely detected at many wavelengths. With improvements in the computer technology, the galaxy images moved from conventional photographic plates to computer files with digitized data. The chemical processes on the plates were now replaced with electron counts by charge coupled devices (CCDs) bringing the detection efficiency close to 100%.

With the improved technology and quality of data, the quantity of data being archived also started to increase rapidly. The classification of this data, which is done manually, has become tedious and time consuming and has started to call for an automated process of classification.

Fractal dimension is a mathematical quantity directly related to the complexity of a given data set. Classification of galaxies, discussed in chapter 2, is based on the morphology of the galaxies. It is also related to the complexity of their shapes. In this project, fractal dimensions of galaxies were computed for a data set of galaxies and conclusions were derived for the automated classification possibilities of galaxies using fractal dimensions.


next up previous contents
Next: GALAXY CLASSIFICATION SCHEMES Up: CLASSIFICATION OF GALAXIES USING Previous: List of Figures
Sandip Thanki
1999-07-29