Thesis (Ph.D.) -- University of Western Sydney, 2002. / "Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy, University of Western Sydney" Bibliography.

Thesis (M. Phil.)--University of Hong Kong, 2007. / Title proper from title frame. Also available in printed format.

Thesis (Ph. D.)--Ohio State University, 2005. / Title from first page of PDF file. Document formatted into pages; contains xx, 198 p.; also includes graphics (some col.). Includes bibliographical references (p. 191-198). Available online via OhioLINK's ETD Center.

Thesis (Ph. D.)--Rochester Institute of Technology, 2007. / Typescript. Includes bibliographical references (leaves 123-129).

Using the Chandra X-ray Observatory, Martini et al. (2006) found that the AGN fraction of galaxy clusters was five times higher than previous optical studies suggested. Using visual observations only, Dressler et al. (1985) estimated the AGN fraction of field galaxies to be 5%, while that of clusters was thought to be 1%. To understand the role that the environment plays in AGN fueling, the author studied a variety of environments, ranging from the field to groups to clusters. Will the AGN fraction of groups also be higher than that of the field? The author demonstrates how the AGN fraction of groups compares to that of clusters. In the following sections, the author describes the mechanics of X-ray astronomy, the group environment, and the characteristics of active galactic nuclei. The author briefly describes the possible mechanisms for AGN fueling.

Hard X-ray spectra of accreting black holes in active galactic nuclei and X- ray binaries are characterized by a power-law shape with an exponential cut-off energy at several tens up to few hundreds of keV. The value of the cut-off energy is related to the temperature of a hot corona that reprocesses and inversely Comptonizes thermal emission from the accretion disc. The exact geometry of the corona is still unknown. Several observations suggest it to be very compact and in a close proximity to the black hole. This implies strong relativistic effects such as gravitational redshift, Doppler shift, light bending and beaming to shape the resulting spectra. However, the relativistic effects on primary X-ray emission are often neglected in the data spectral fitting. In this work, we investigate how large uncertainty is introduced by neglecting these relativistic effects. To this purpose, we performed simulations of X-ray spectra for different coronal geometries, and compared the intrinsic and observed values of the cutoff energy. We re-analyzed NuSTAR observations of an active galactic nucleus 1H0419-577 and X-ray binary GRS 1915+105. We found that the extremely low coronal temperatures observed in these sources may be explained by the gravitational redshift due to the proximity of the compact corona to the black hole....

京都大学 / 新制・課程博士 / 博士(理学) / 甲第22995号 / 理博第4672号 / 新制||理||1670(附属図書館) / 京都大学大学院理学研究科物理学・宇宙物理学専攻 / (主査)教授 鶴 剛, 准教授 窪 秀利, 教授 中家 剛 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM

京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第19497号 / 理博第4157号 / 新制||理||1597(附属図書館) / 32533 / 京都大学大学院理学研究科物理学・宇宙物理学専攻 / (主査)教授 鶴 剛, 教授 谷森 達, 准教授 成木 恵 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM

京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第20912号 / 理博第4364号 / 新制||理||1626(附属図書館) / 京都大学大学院理学研究科物理学・宇宙物理学専攻 / (主査)教授 井岡 邦仁, 教授 川合 光, 教授 田中 貴浩 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

京都大学 / 新制・課程博士 / 博士(理学) / 甲第24407号 / 理博第4906号 / 新制||理||1701(附属図書館) / 京都大学大学院理学研究科物理学・宇宙物理学専攻 / (主査)教授 鶴 剛, 准教授 細川 隆史, 教授 永江 知文 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM