Related papers: Interplay Between Chaotic and Regular Motion in a …
(Abridged) The Galactic bar causes a characteristic splitting of the disc phase space into regular and chaotic orbit regions which is shown to play an important role in shaping the stellar velocity distribution in the Solar neighbourhood. A…
We perform a detailed study of the chaotic component in mixed-type Hamiltonian systems on the example of a family of billiards [introduced by Robnik in J. Phys. A: Math. Gen. 16, 3971 (1983)]. The phase space is divided into a grid of cells…
This paper discusses three new issues that necessarily arise in realistic attempts to apply nonlinear dynamics to galaxy evolution, namely: (i) the meaning of chaos in many-body systems, (ii) the time-dependence of the bulk potential, which…
In this paper, we implement a generalised pseudo-Newtonian potential to study the off-equatorial orbits inclined at a certain angle with the equatorial plane around Schwarzschild and Kerr-like compact object primaries surrounded by a…
We analyze the orbital dynamics of spherical test bodies in ``black hole surrounded by dark matter halo'' spherically symmetric spacetimes. When the test body pulsates periodically (such as a variable star), altering its quadrupole tensor,…
We examine the observable properties of simulated barred galaxies including radial mass profiles, edge-on structure and kinematics, bar lengths and pattern speed evolution for detailed comparison to real systems. We have run several…
Understanding the dynamics of multi--dimensional conservative dynamical systems (Hamiltonian flows or symplectic maps) is a fundamental issue of non-linear science. The Generalized ALignment Index (GALI), which was recently introduced and…
We study the mechanisms and evolutionary phases of bar formation in n-body simulations of a stellar disc and dark matter halo system using harmonic basis function expansion analysis to characterize the dynamical mechanisms in bar evolution.…
In the present article, we investigate the behavior of orbits in a time independent axially symmetric galactic type potential. This dynamical model can be considered to describe the motion in the central parts of a galaxy, for values of…
A new dynamical parameter, the f-indicator, is introduced and used in order to distinguish between regular and chaotic motion in galactic Hamiltonian systems. Two kinds of galactic potentials are used: (i) a global potential, which…
We investigate the stability of trajectories in barred galaxies with mildly triaxial halos by means of Liapunov exponents. This method is perfectly suitable for time-dependent 3D potentials where surfaces of sections and other simple…
A well-behaved adjoint sensitivity technique for chaotic dynamical systems is presented. The method arises from the specialisation of established variational techniques to the unstable periodic orbits of the system. On such trajectories,…
Using an N-body+SPH code we have performed numerical simulations to investigate the dynamical effects of an interaction between an initially barred galaxy and a small spherical companion. In the models described here the small companion…
It is a well established result that, in classical dynamical systems with sufficient time-scale separation, the fast chaotic degrees of freedom are well modeled by (Gaussian) white noise. In this paper, we present the stochastic dynamical…
Galactic bars are found in the majority of disc galaxies. They rotate nearly rigidly with an angular frequency called pattern speed. Previous idealised simulations have shown that bar pattern speed decreases with time due to dynamical…
Many barred galaxies, including the Large Magellanic Cloud (LMC), display strong lopsidedness and off-centre bars. The dynamical connection between bar-disc misalignments, internal mass asymmetries, and arm morphology is not yet fully…
We investigate the evolution of phase space close to complex unstable periodic orbits in two galactic type potentials. They represent characteristic morphological types of disc galaxies, namely barred and normal (non-barred) spiral…
Observational evidence strongly supports the existence of a Super Massive Black Hole (SMBH) at the Galactic center, surrounded by dense stellar clusters. Modeling galactic centers with intricate structures like shells and rings pose…
Celestial bodies approximated with rigid triaxial ellipsoids in a two-body system can rotate chaotically due to the time-varying gravitational torque from the central mass. At small orbital eccentricity values, rotation is short-term…
High resolution N-body simulations using different codes and initial condition techniques reveal two different behaviours for the rotation frequency of transient spiral arms like structures. Whereas unbarred disks present spiral arms nearly…