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Paper: Midplane Stellar Orbits and the Galactic Mass Distribution in the Presence of 3D Spiral Arms
Volume: 282, Galaxies: The Third Dimension
Page: 169
Authors: Pichardo, B.; Moreno, E.; Martos, M.
Abstract: We have assembled a model for the Galactic mass distribution adding a spiral pattern and a central bar to an axysimmetric background model for the galactic potential. Our non axisymmetric components are modeled as a superposition of spheroids and a triaxial structure. A family of models was constructed in a plausible range of observational (such as the spiral pitch angle,rotation curve, the vertical structure of the thick disk) and theoretical (self consistency) constraints for the Galaxy. Studying the stellar orbital structure, we find that our Galaxy is a strong spiral, and thus chaos is possible even for planar orbits such as that of the Sun, but only for prograde orbits with respect to the spiral pattern rotation. Studying possible gas trajectories in our model, we are able to study in great detail several outstanding problems in galactic structure: tracing the magnetic field 3D structure by imposing MHD vertical and radial equilibrium; the corotation of gas at high z (distance above the midplane); the complex kinematics at the inner Lindblad resonance; the magnetized gas response to the spiral density wave; and the possibility of magnetic dynamical support to the rotation curve and new limits to the amount of dark matter if magnetic tension indeed has an important contribution at large R.
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