GLOBAL DYNAMICS IN A SELF–CONSISTENT MODEL OF ELLIPTICAL GALAXY

PABLO CINCOTTA; CLAUDIA GIORDANO; JUAN C. MUZZIO

Discrete and Continuous Dynamical Systems - Series B

American Institute of Mathematical Sciences

Año: 2008 vol. 10 p. 439 - 454

1531-3492

In the present paper we study the global dynamics correspondingto a realistic model of self–consistent triaxial galactic system. We extend aprevious work [17] where the authors investigate 3,472 orbits in this model atdifferent energy levels, using Lyapunov exponents to measure chaoticity andfrequency analysis to classify regular orbits. Here we first display the mainproperties of that potential and then focus our attention on the global dynamicalfeatures of the box domain for nine energy surfaces. Using the MEGNOas a fast dynamical indicator, we gain insight in the resonance structure atdifferent energy levels, the way in which relatively large chaotic domains arisedue to overlapping as well as crossings of resonances and we measure the fractionof chaotic motion in the energy space. It is interesting to notice that theflatness of the model varies over a rather wide range, namely from  0.5 to 1, and the fraction of chaotic motion ranges from  0.15 at small energiesup to  0.75 at moderate values of the energy, decreasing then again down tovalues close to  0.4 where the system becomes nearly spherical.