Axisymmetric oscillation modes of relativistic tori in the vicinity of a distorted, deformed compact object

Abstract

ABSTRACT This paper studies the oscillation properties of relativistic, non-self-gravitating tori in the background of a distorted, deformed compact object. This work concentrates on a static and axially symmetric metric containing two quadrupole parameters; relating to the central object and the external fields. This metric may associate the observable effects of these parameters as dynamical degrees of freedom. The astrophysical motivation for choosing such a field is the possibility of constituting a reasonable model for an actual scenario occurring in the vicinity of compact objects. Following our previous works, this paper aims to investigate the radial epicyclic frequency in a perfect fluid disc and not a test particle scenario via a local analysis. To achieve this goal, we employ the vertically integrated technique to be able to treat the equations analytically. The tori configuration is also modelled with Keplerian and non-Keplerian distributions of specific angular momentum. In this set-up, we also discuss the dependence of oscillation properties on the model’s variables related to angular momentum distribution and quadrupoles. In the present contribution, we further explore these properties with the possibility of relating oscillatory frequencies to some high-frequency quasi-periodic oscillations models and observed data in some microquasar and neutron star sources, and test the ability of this fluid approach to fit with observational data.