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Mass estimation, dynamics and feedback in galaxy groups

Pearson, Richard John (2015)
Ph.D. thesis, University of Birmingham.

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Accurate mass estimates for galaxy groups and clusters are important for understanding the evolution of matter within the universe. In this thesis we first discuss methods of mass estimation currently used within the literature, and introduce a set of scaling relations for mass estimation in cases where literature methods are not applicable. We find that methods based on group richness provide the best (i.e. lowest scatter) mass estimator.
Secondly, we study the impact of feedback on hot group gas for a sample of optically selected groups. We refine the group selection using their dynamical state, identified through substructure in the distribution of member galaxies. We find this sample to be underluminous compared to an X-ray selected sample. Furthermore, with two groups showing high 2σ lower limits on entropy, the population of high entropy groups predicted by hydrodynamical simulations may have been detected.
Finally, we combine measures of dynamical state and mass estimation scaling relations to understand how the presence of substructure can impact upon the ability to reliably estimate group and cluster masses. We find that substructure introduced through poor group identification has the largest effect on the quality of the final mass estimates.

Type of Work:Ph.D. thesis.
Supervisor(s):Ponman, Trevor A.
School/Faculty:Colleges (2008 onwards) > College of Engineering & Physical Sciences
Department:School of Physics and Astronomy, Astrophysics and Space Research
Subjects:QB Astronomy
Institution:University of Birmingham
ID Code:5676
This unpublished thesis/dissertation is copyright of the author and/or third parties. The intellectual property rights of the author or third parties in respect of this work are as defined by The Copyright Designs and Patents Act 1988 or as modified by any successor legislation. Any use made of information contained in this thesis/dissertation must be in accordance with that legislation and must be properly acknowledged. Further distribution or reproduction in any format is prohibited without the permission of the copyright holder.
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