The Correlation Between Intrinsic X-ray Photon Index And Eddington Ratio For AGNs

In this thesis we construct a bright AGN sample in the ECDFS and CDFN fields,and derive X-ray properties for these AGNs such as intrinsic photon index,neutral Hy-drogen column density,and intrinsic X-ray luminosity through detailed X-ray spectral analyses.We find an average photon index of 1.72± 0.01 for this sample,and investi-gate the relations between various X-ray physical parameters.We compare our results with previous works.We also compile multiwavelength data for these sources,and perform SED fitting utilizing Chi-squared minimization in order to decompose the contributions of galaxies and AGNs.Through SED decomposition,we obtain additional physical parameters,including,e.g.,galaxy stellar mass,galaxy age,and the optical luminosity of AGNs.For the sources with accurate estimates of black hole mass,we combine these data and the data of galaxy mass,and find that the relation between the mass of the central supermassive black hole and the mass of the galaxy is almost the same as the relation obtained in the local universe,which suggests that such a relation is not evolutionary.Using the obtained data,we construct a larger and more uniform AGN sample than previous works to study the relation between intrinsic X-ray photon index and Edding-ton ratio.We find that for those low-luminosity AGNs the photon index is inversely correlated with Eddington ratio.However,for those more luminous AGNs the two physical parameters are positively correlated,though the correlation is not so obvious.This finding has been demonstrated by many authors before,but our work extends this relation into a higher-redshift regime based on a substantial sample.The difference in the coefficients of this relation from previous works is discussed within the context of accretion theories.