The Role of Flyby Interactions in Shaping Galaxy Evolution

Abstract

Galaxy interactions play a critical role in the growth and evolution of galaxies. While galaxy mergers are known to transform galaxies morphologically and kinematically in a myriad of ways, not all interactions lead to a merger. Flybys, for example, are interactions where the galaxies’ dark matter halos interpenetrate, but later disconnect. Despite evidence that flybys could be as common as mergers for some halos (Sinha & Holley-Bockelmann 2012), little is known about how flybys affect galaxies. Using high resolution N-body simulations, this thesis presents findings that flybys are capable of triggering bars that can survive long after the interaction is complete. Given that bars drive galaxy evolution, flybys are likely an important component of galaxy evolution that has largely been discounted. In addition to exploring the impact of flybys, this thesis also includes two projects which support the larger goal to further our understanding of galaxy interactions as a whole. The first explores the plausibility of a single minor merger in the Milky Way’s recent past as an explanation for observed phenomena surrounding the Galactic Center. The second presents TesseRACt, a non-parametric technique for measuring the concentration of simulated dark matter halos.