Thesis (Ph.D.) - Cairo University - Faculty of Science - Department of Astronomy and Meteorology

This study is mainly concerned with studying some aspects of quasars evolution, e.g X- ray spectral properties of quasars (QSOs), Supermassive Black hole (SMBHs) and how the properties of quasars evolve as a function of red shift. We focus on X-ray evolution of spectral properties of QSO as a function of red shift. Our main objective is to establish a new X-ray database of quasars. The total X-ray samples used in our new database is much more than the data obtained in the previous studies. The huge databases helped us to investigate the globular properties of QSOs that are measured in optical and X-ray as a function of red shift. We have found from the quasars distribution as a function of red shift that there is a small number of quasars at 2 < Z < 3, and Z > 5, while the number increases largely at Z < 2 and 3 < Z < 5. This result indicates the importance of observing quasars using X-ray at ranges of red shift that has small numbers in future research.

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