| Abstract : | Approximately two-third of galactic disks feature a central mass component known as bar. The quadrupole moment associated with the gravitational potential of the bar helps in angular momentum transport and,hence, in the secular evolution of galaxies. Dynamical modelling of the observed structure and kinematics indicates that the bar rotates about the galactic centre as a rigid body; the stars therein mostly stream along the highly eccentric orbits co-aligned with its major axis. The dynamics of stars in the galactic bar are complex, often exhibiting chaotic behaviour, making analytical study challenging. We use the Schwarzschild modelling method to understand chaos in bar dynamics from the perspective of orbits. The Schwarzschild method has been widely applied to model the dynamics of early-type galaxies. The technique is most developed and well-tested, which is free from most of the assumptions, observables can be calculated efficiently, and the numerical integrals are well understood, which makes it computationally easy. Also, it is a practical method
for constructing triaxial stellar systems in dynamical equilibrium. The Schwarzschild modelling method has not been applied to the Integral Field Unit data extensively. For the barred galaxy NGC 4303 from the TIMER MUSE IFU survey, we use the Python package FORSTAND (Flexible orbit superposition toolkit for assessing dynamical models) for implementing Schwarzschild modelling. Our model comprises non-luminous dark matter, described by NFW profile, and luminous component (stars + bar), specified by density profile from Multi-Gaussian-Expansion (MGE). The models remarkably well fit all the obtained kinematic data. The modelling yields a consistent bar pattern speed of Ωp = 0.75Kms−1arcsec−1, within the error range of earlier investigations. |
