Host galaxies and environment of active galactic nuclei : a study of the XMM large scale structure survey

Abstract

Active galactic nuclei (AGN) result from the infall of matter onto the super-massive black holes that are situated at the centres of galaxies. This process releases an enormous amount of energy into the inter-stellar and inter-galactic medium. Hence, the study of AGN becomes essential in the context of galaxy formation theories. With the advent of large astronomical surveys, it has become possible to study many of their properties in great detail. In this thesis, we study the host galaxies and environment of AGN populations in the XMM-LSS multi-wavelength survey. Our aim is to address the following questions: How are the different classes of AGN distributed within the large scale structure of the Universe? What are the mechanisms that trigger AGN activity? Are there connections between triggering processes and AGN properties such as the accretion mode? How have these relations evolved through cosmic time?