We generate a suite of idealized two-body X-ray cluster merger simulations with which we study the impact of mergers on the properties of relaxed X-ray clusters. We identify a common dynamical progression which typical merger events proceed through and use simulated Chandra observations to identify observable transient structures in surface brightness, temperature and entropy which emerge in the process. These simulated observations are also used to determine when the systems would appear relaxed under reasonable observational circumstances. This time is compared to other, more quantitative measures of a system's apparent dynamical state, all of which are compared to the time when the system formally relaxes to a virialized or hydrostatic state. The effects of mergers on observable X-ray and Sunyaev-Zel'dovich (SZ) observables are then explored and the contribution of merger events on scaling relations generated from these quantities examined. We conclude that mergers are likely not capable of accounting for the observed scatter in these relations. We then examine the effects of mergers on the morphology and structure of compact cool cores (CCCs) observed to be present in the majority of X-ray clusters. We find that mergers can warm CCC systems, potentially transforming them (either transiently or for extended periods) into two additional morphologies: extended warm core (EWC) and compact warm core (CWC) systems. These morphologies segregate in all scaling relation planes in a way which is qualitatively consistent with what is observed. Lastly, we find that mergers do not efficiently mix the intracluster medium (ICM). Mergers between systems which initially possess central metalicity gradients (as CCC systems generally do) produce remnants with metalicity gradients very similar to those of the parent systems. Together. these results pose a. significant challenge to a popular hypothesis in X-ray cluster studies: that mergers are responsible for producing extended core systems.
| Identifer | oai:union.ndltd.org:uvic.ca/oai:dspace.library.uvic.ca:1828/2217 |
| Date | 18 February 2010 |
| Creators | Poole, Gregory B. |
| Contributors | Babul, Arif |
| Source Sets | University of Victoria |
| Language | English, English |
| Detected Language | English |
| Type | Thesis |
| Rights | Available to the World Wide Web |
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