Radial and vertical epicyclic frequencies of Keplerian motion in the field of Kerr naked singularities - comparison with the black hole case and possible instability of naked singularity accretion discs

TL;DR

This paper investigates the orbital and epicyclic frequencies around Kerr naked singularities, comparing them with black holes, to identify potential observational signatures and assess the stability of accretion disks in these exotic spacetimes.

Contribution

It analyzes the fundamental frequencies of Keplerian motion in Kerr naked singularities, highlighting phenomena that could distinguish them from black holes observationally.

Findings

Existence of strong resonant frequencies in Kerr naked singularities

Radial and vertical epicyclic frequencies are equal at specific radii

Potential instability of naked singularity accretion disks

Abstract

Relativistic Keplerian orbital frequency and related epicyclic frequencies play an important role in physics of accretion discs orbiting Kerr black holes and can by resonant or trapping effects explain quasiperiodic oscillations observed in microquasars. Because of growing theoretical evidence on possible existence of naked singularities, we discuss behaviour of the fundamenal orbital frequencies for Keplerian motion in the field of Kerr naked singularities, primarily in order to find phenomena that could observationally distinguish a hypothetical naked singularity from black holes. Some astrophysically important consequences are sketched, namely the existence of strong resonant frequency for all Kerr naked singularities, with radial and vertical epicyclic frequencies being equal at well defined radius.