Exploring the Nature of Fossil Galaxy Systems with Simulations and X-ray Observations
Abstract
Fossil galaxy groups and clusters are characterized by an extreme difference in brightness between their central and satellite galaxies. This magnitude gap has been proposed to form as the result of significant mergers of massive satellite galaxies with the central galaxy over time which suggests fossils represent an interesting stage of galaxy system evolution and hierarchical structure formation. The objective of this thesis is to use X-ray observations and simulations to constrain the properties of fossil galaxy systems with the goal of understanding their nature and origin. In this thesis, the properties of fossil systems are first examined by constructing the global optical and X-ray scaling relations of fossils across the group and cluster mass regimes. Then, using the Illustris cosmological simulation, the mass assembly histories of fossil central galaxies and their group halos are traced directly. Lastly, the X-ray properties of fossil system RX J1159.8+5531 are investigated in detail through radial profiles of intracluster medium temperature and density, which are used to determine the total mass profile and mass concentration parameter of this group. These studies point towards fossil systems as a temporary relaxed state in the evolution of galaxy groups and clusters.
- Publication:
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Ph.D. Thesis
- Pub Date:
- 2018
- Bibcode:
- 2018PhDT........72K
- Keywords:
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- Astronomy;Astrophysics