Probing high-velocity outflows in active galactic nuclei and their relationship to the inner disc environment with X-ray observations

Abstract

High-velocity outflows in active galactic nuclei usually manifest as either a collimated jet or diffuse wind. These outflows carry a significant amount of energy from the central environment surrounding the supermassive black hole into the host galaxy, potentially altering the course of star formation therein. Our current understanding of how these outflows relate to the central engine, however, remains incomplete. We do not know why some active galactic nuclei exhibit jets, why some have winds, how either outflow responds to changes in the conditions of the X-ray emitting region, and if the ones that have no outflows are intrinsically different systems. In Chapters 2 and 3, I present case studies of two radio-loud active galaxies with jets, III Zw 2 and IRAS 17020+4544, in an effort to explore the postulated disc-jet connection in such systems using X-ray observations. Spectral and variability properties in each source suggest that an outflowing X-ray source may act as the jet base. In a future work, this interpretation will be explored using a sample of both radio-loud and radio-quiet sources to test its validity. A sample of 20 active galaxies that have been previously reported as exhibiting ultra-fast winds in their X-ray spectra is used to probe what underlying driving mechanisms may produce such outflows, as well as how the outflow properties relate to the conditions of the central engine. We find that wind properties are closely linked to a variety of source parameters, such as accretion rate and disc inclination angle. The properties of six extreme accretors may suggest non-standard accretion disc scenarios for which no wind is necessary, highlighting the need to explore alternative models. Future X-ray missions with enhanced spectral resolution will enable more accurate determinations on the energetics and locations of these extreme winds, which are ill-constrained with current data.