PDF, English - main document Restricted access: Repository staff only until 1 July 2025. Login+Download (27MB) | Lizenz: Pathways to Supermassive Black Hole Growth - Resolving Gas Flows and Black Hole Mass Scaling Relations in AGN Host Galaxies by Winkel, Nico underlies the terms of Creative Commons Attribution-NonCommercial-NoDerivatives 4.0

Abstract

Supermassive black holes (SMBHs) with masses ranging from millions to billions of times that of the Sun exist at the centres of most massive galaxies, including our Milky Way. Various scaling relations between SMBH mass (MBH) and host galaxy properties suggest a coevolution between them. A key factor in establishing these relations may be the periods during which SMBHs accrete significant amounts of gas, a process that manifests as luminous Active Galactic Nuclei (AGNs). The transport of gas towards the SMBH is believed to be regulated by processes within the host galaxy, while feedback from the AGN influences the galaxy’s evolution in return. While such processes have been resolved in the centres of nearby low-luminosity AGNs, their low accretion rates are insufficient to grow a SMBH. To better understand the processes driving the growth of SMBHs and their host galaxies across cosmic time, it is essential to study AGNs with high specific accretion rates. In this thesis, I demonstrate how high-spatial-resolution 3D spectroscopic observations are used to achieve this goal. In Mrk 1044, a nearby AGN accreting at high specific rates, the ionized gas kinematics and spiral morphology suggest that star formation drives material toward the AGN. A spectroastrometric analysis reveals a parsec-scale ionized gas outflow, indicating that the AGN is in an early stage of evolution. In NGC 4593, ALMA observations uncover abundant molecular gas extending from the kpc-scale galaxy bar into the BH sphere of influence. I analyse the star formation efficiency, gas kinematics, and mass inflow rates, and discuss various mechanisms that may enable this AGN feeding mode. Finally, I present a recalibration of the relation between MBH and host galaxy stellar velocity dispersion. By combining independently measured MBH with unprecedented integral-field spectroscopic data from Keck/KCWI, VLT/MUSE and VLT/VIMOS, I demonstrate for the first time that AGNs and quiescent galaxies follow the same underlying scaling relations, providing a baseline for measuring SMBH masses across cosmic time. The advancements in observational methods and analysis techniques utilised in this work offer a blueprint for studying the connection between luminous AGNs and their host galaxies. Building on these pilot studies, new observations aimed at a comprehensive census of gas flows in nearby quasars will begin in October 2024, laying the groundwork for future research.