The origin and evolution of galaxies are closely linked to many different physical phenomena. Among them, the most important one is the environment they reside in. Isolated and cluster member... Show moreThe origin and evolution of galaxies are closely linked to many different physical phenomena. Among them, the most important one is the environment they reside in. Isolated and cluster member galaxies indeed are affected by different forces which affect their evolution. The main concern of this thesis is to understand such forces and how they are related to galaxy evolution. Therefore, this thesis covers various topics including black hole mass calculations, the black hole mass-stellar velocity dispersion relation, the nature of AGN emission in galaxy clusters and field galaxies, a detailed investigation of X-ray and optical galaxy overdensity phenomenon, and the dynamical processes in pre-merging galaxy clusters. Show less
In astronomy, the interpration of observations and measurements plays a crucial role: we rely purely and fundamentally on the information that reaches us as observers. And 80% of all matter in the... Show moreIn astronomy, the interpration of observations and measurements plays a crucial role: we rely purely and fundamentally on the information that reaches us as observers. And 80% of all matter in the universe is undetectable directly.This so called 'dark matter' can be observed indirectly, by the gravitational effect on its surroundings and the curvature of spacetime predicted by the theory of relativity.In this thesis, we combine scientific research, a description of our universe, with theoretical considerations of the statistical methods used for that research, or how we can deduce that description from the 'reflections' that we see. In this work, we focus on the matter distribution in groups and clusters of galaxies, and consider the intricacies of the method of weak gravitational lensing that we use, respectively. Show less
This thesis deals with the cool gas, i.e. less than 10000 degrees Kelvin, at the centres of relaxed, rich galaxy clusters. We find that a significant amount of this gas exists within a 50... Show moreThis thesis deals with the cool gas, i.e. less than 10000 degrees Kelvin, at the centres of relaxed, rich galaxy clusters. We find that a significant amount of this gas exists within a 50 kiloparsec nebula centered on the Brightest Cluster Galaxy. The cool gas is locked up in long, thin filaments and exists in three phases, i.e. ionised, atomic and molecular, that share the same extent and dynamics. The bright line emission of this gas implies rapid cooling. However, the inferred cooling rates are not in line with observations and therefore this gas requires continues reheating. The total reheating necessary rivals that of the hot X-ray emitting phase. Several sources of reheating are investigated with heating by X-rays or Cosmic rays being the most promising candidates Show less
