The properties of emission lines and their correlations in spectra of Active Galactic Nuclei

Active Galactic Nuclei (AGNs) are the most luminous objects in the Universe. It is assumed that an AGN consists of a supermassive black hole in the center, surrounded by accreating gas. In that process, a large amount of energy is produced, resulting in a very complex spectrum that shows a number of strong emission lines, which arise in the plasma located close to the supermassive black hole. Here we analyse the line profile shapes, which are signature of the geometry, physical and kinematical properties of the AGN emission gas. Especially we analysed the optical Fe II lines, in order to answer to some unexplained questions about their origin. We found correlations between line properties which physical background is still not explained. Possible influence of starbursts to AGN spectral properties is discussed.