Research Division Seminar
Fuelling supermassive black holes with galaxy interactions
Interactions between galaxies often leave an imprint that is observable in the aftermath of the interaction, such as tidal features or perturbations in the stellar and gas kinematics of the galaxies. Sometimes these perturbations can be structures (i.e. gas or stars) that are strongly misaligned or even rotating in the opposite direction with respect to the main stellar body of the galaxy. It has been suggested by simulations that misalignment may drive galaxy gas all the way to the central supermassive back hole, one of the ingredients needed to fuel black hole activity. I will show observational evidence that galaxy interactions, such as major mergers, minor mergers or galaxy flybys, indeed provide the necessary conditions to fuel black hole activity and growth. I will present a method that uses kinematically misaligned gas to observationally identify galaxies that went through an interaction. With this method we have recently shown that galaxies that have misaligned gas have a higher observed fraction of active black holes. This is the first time that an observational connection is seen between the process of formation and/or presence of misaligned structures and the fuelling of active supermassive black holes. I will discuss the implications of this black hole fuelling mechanism for different galaxy types and their evolution.