TY - THES A1 - Krumpe, Mirko T1 - X-ray and optical properties of X-ray luminous active galactic nuclei Y1 - 2008 DO - 10.23689/fidgeo-63 PB - Univ. Potsdam N2 - Giacconi et al. (1962) discovered a diffuse cosmic X-ray background with rocket experiments when they searched for lunar X-ray emission. Later satellite missions found a spectral peak in the cosmic X-ray background at ~30 keV. Imaging X-ray satellites such as ROSAT (1990-1999) were able to resolve up to 80% of the background below 2 keV into single point sources, mainly active galaxies. The cosmic X-ray background is the integration of all accreting super-massive (several million solar masses) black holes in the centre of active galaxies over cosmic time. Synthesis models need further populations of X-ray absorbed active galaxy nuclei (AGN) in order to explain the cosmic X-ray background peak at ~30 keV. Current X-ray missions such as XMM-Newton and Chandra offer the possibility of studying these additional populations... UR - http://hdl.handle.net/11858/00-1735-0000-0001-30C4-C ER -