Stellar Orbits in Barred Galaxies with Nuclear Rings

We investigate the dynamical response of stellar orbits in a rotating barred galaxy potential to the perturbation by a nuclear gaseous ring. The change in 3D periodic orbit families is examined as the gas accumulates near the inner Lindblad resonance. It is found that the x2/x3 loop extends to higher Jacobi energy and a vertical instability strip forms in each family. These strips are connected by a symmetric/anti-symmetric pair of 2:2:1 3D orbital families. A significant distortion of the x1 orbits is observed in the vicinity of the ring, which leads to the intersection between orbits over a large range of the Jacobi integral. We also find that a moderately elliptical ring oblique to the stellar bar produces significant phase shifts in the x1 orbital response.