Distinguishing between order and chaos in a simple barred galaxy model
  We use a simple dynamical model in order to investigate the regular or
chaotic character of orbits in a barred galaxy with a central, spherically
symmetric, dense nucleus and a flat disk. In particular, we explore how the
total orbital energy influences the overall orbital structure of the system, by
computing in each case the percentage of regular, sticky and chaotic orbits. In
an attempt to distinguish safely and with certainty between ordered and chaotic
motion, we apply the Smaller ALingment Index (SALI) as a chaos detector to
extensive samples of orbits obtained by integrating numerically the basic
equations of motion as well as the variational equations. We integrate large
sets of initial conditions of orbits in several types of two dimensional planes
for better understanding of the orbital properties. Our numerical calculations
suggest, that the value of the energy has a huge impact on the percentages of
the orbits, thus indicating that a rotating barred galaxy is indeed a very
interesting stellar quantity.
