TY  - BOOK
AU  - Nasser Ahmed Nasser Abuseif
AU  - Anas Mohamed Osman , 
AU  - Mohamed Rassem , 
TI  - Investigate the evolution of spectral propertiesand extremely high accretion rates of supermassive black hole quasars as a function of redshift / 
PY  - 2015///
CY  - Cairo : 
PB  - Nasser Ahmed Nasser Abuseif , 
KW  - Quasars
KW  - Red Shift
KW  - X-ray spectral properties
N1  - Thesis (Ph.D.) - Cairo University - Faculty of Science - Department of Astronomy and Meteorology; Issued also as CD
N2  - 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.
UR  - http://172.23.153.220/th.pdf
ER  -