Valenzuela, Lucas
Germany – Universitäts-Sternwarte München
A Stream Come True: Tidal features and inner kinematics as tracers of galaxy formation
Through the large improvements of low surface brightness observations and of cosmological simulations of galaxies in the last decade, it has become possible to study the unrelaxed outskirts of galaxies in more detail and connect them with their formation history. Additionally, integral field unit measurements of the inner kinematics of galaxies have enabled the study of this further tracer of galaxy formation. Using a first complete census of several tidal feature types in a hydrodynamical cosmological simulation including shells, streams, and tails, I will show how these imprints in the outskirts of galaxies are related to the inner kinematics. These results are in agreement with those found in observations such as the MATLAS survey and surveys targeting BCGs. I will present how tidal shells are directly linked to major mergers on radial infall orbits that in many cases lead to the transition of the host galaxy to a slow rotator. As a result, shells are most commonly found around dispersion dominated systems. Through a kinematic classification of the inner galaxy regions, trends emerge between the kinematic classes and the presence of tidal features in the outskirts: while prolate rotators are the most likely to have tidal features in their outskirts in general, galaxies with a kinematically distinct core are the most likely to feature tidal streams around them. Finally, I will discuss possibilities of detecting tidal features through kinematic studies of the outskirts, for example by resorting to the more easily identifiable planetary nebulae or globular clusters.