Symbioses or not? Supermassive black hole growth in nearby galaxies

Supervisor: Sabine Thater and Glenn van de Ven (Department of Astrophysics), in collaboration with Jonelle Walsh (Texas A&M University) and Rhea-Silvia Remus (LMU Munich)

Funding Situation: potentially via a VISESS PhD fellowship

Project outline: Supermassive black holes (SMBH) are found in the centers of massive galaxies and if they are in an active state produce gigantic amounts of energies that interact with the host galaxy and may affect its growth. Inactive SMBHs lie dormant in the galaxy centers and can only be detected based on their gravitational influence on the surrounding stars and gas. By now about 150 SMBH masses have been measured dynamically for all types of galaxies using different measurement methods. Those masses have been used to identify tight scaling relations between SMBHs and their host galaxy properties suggesting coevolution. It is not clear if this happened symbiotic with SMBHs growing together with their host galaxies, or if the galaxy grew first and the SMBH caught up, or the SMBH grew first and the galaxy assembled around it.

The goal of this PhD project is to understand the coevolution by looking for evidence of the past interactions and growth channels for both the SMBH and its host galaxy using observations and simulations. For testing the different scenarios, we will closely investigate the observed properties of the SMBH and its host galaxy and compare them with simulated galaxies. The student will learn how extend the current SMBH sample with homogeneous mass measurements of nearby galaxies in a similar fashion to Thater et al. 2019 ( extracting stellar kinematics from already obtained high-resolution near-infrared and optical integral-field spectroscopic data and using them to construct dynamical models. The student will also apply the chemo-dynamical Schwarzschild code developed in our research group to arrive at a more physical measurement of the host galaxy properties, i.e., also improve on the horizontal axis of the scaling relation versus black hole mass on the vertical axis.