Oscillations of non-slender tori in the external Hartle-Thorne geometry

TL;DR

This paper investigates how the quadrupole moment of a slowly rotating neutron star affects the oscillation frequencies of non-slender accretion tori, with implications for understanding high-frequency QPOs in X-ray binaries.

Contribution

It provides analytical calculations of radial epicyclic frequencies of tori in Hartle-Thorne geometry, extending previous models to include quadrupole effects.

Findings

Calculated frequencies differ from Kerr-based models.

Preliminary results show quadrupole influence on oscillation modes.

Discussion on implications for QPO models.

Abstract

We examine the influence of the quadrupole moment of a slowly rotating neutron star on the oscillations of non-slender accretion tori. We apply previously developed methods to perform analytical calculations of frequencies of the radial epicyclic mode of a torus in the specific case of the Hartle-Thorne geometry. We present here our preliminary results and provide a brief comparison between the calculated frequencies and the frequencies previously obtained assuming both standard and linearized Kerr geometry. Finally, we shortly discuss the consequences for models of high-frequency quasi-periodic oscillations observed in low-mass X-ray binaries.