Applying the manifold theory to Milky Way models: First steps on morphology and kinematics

¹ Dept. d’Astronomia i Meteorologia & Institut de Ciències del Cosmos, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain
² Laboratoire d’Astrophysique de Marseille, UMR6110, CNRS/Université de Provence, 38 rue Frédéric Joliot Curie, 13388 Marseille, France
³ Kapteyn Astronomical Institute, University of Groningen, PO Box 800, 9700 AV Groningen, The Netherlands

^a e-mail: mromero@am.ub.es

Abstract

We present recent results obtained by applying invariant manifold techniques to analytical models of the Milky Way. It has been shown that invariant manifolds can reproduce successfully the spiral arms and rings in external barred galaxies. Here, for the first time, we apply this theory to Milky Way models. We select five different models from the literature and, using the parameters chosen by the authors of the papers, and three different cases, namely Case 1, where only the COBE/DIRBE bar is included in the potential; Case 2, when the COBE/DIRBE and the Long bar are aligned, and Case 3, when the COBE/DIRBE bar and the Long bar are misaligned. We compute in each case and for each model the orbits trapped by the manifolds. In general, the global morphology of the manifolds can account for the 3-kpc arms and for the Galactic Molecular Ring.