This thesis studies how the morphologies of a large sample of clusters of galaxies can be used to constrain models of the dynamical evolution of the cluster, the evolution of the cluster galaxies, and the underlying cosmological scenario. Chapter 1 gives the introduction to this thesis and Chapter 2 describes the ROSAT PSPC instrumentation together with the data analysis techniques used. In Chapter 3, the morphology of each cluster is found using isophotal shape analysis on the smoothed image. The morphology is parameterised by the axial ratio, centroid variation and radial fall-off parameter (). The distributions of these parameters for the sample are compared with those predicted by N-body simulations from Mohr et al. (1995) using three different cosmologies. The results from this comparison favour high- cosmologies (i.e., closed universe), with a degree of galactic wind injection into the Intra-Cluster-Medium. However, it should be stressed that the parameters used in the low- simulations are likely to have enhanced the discrepancy between the sample data and the low- models, leading to a biased result. In Chapter 4, the morphology of each cluster is found using radial surface brightness profile fitting, yielding best-fit values for the core radius, and . The correlations of these parameters and other X-ray (e.g. luminosity, temperature) and optical (e.g. galaxy velocity dispersion) parameters are compared to results from previous studies. Analytical models by David et al. (1991b) for the interaction between evolving galaxies and the ICM using a range of Initial Mass Function exponents (x) for the evolving galaxies are also investigated. These comparisons indicate that the most likely scenario is one with an IMF exponent of ~ 1, with galactic winds enriching the energy and Iron content of the ICM.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:696339 |
| Date | January 1997 |
| Creators | Pownall, Helen Rosemary |
| Publisher | University of Leicester |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/2381/30600 |
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