Quasi-periodic oscillations from the accretion disk around rotating traversable wormholes

TL;DR

This paper investigates the unique quasi-periodic oscillation signatures of rotating traversable wormholes, revealing distinctive features that could help differentiate them from black holes through astrophysical observations.

Contribution

It derives analytical expressions for epicyclic frequencies in wormhole spacetimes and compares their oscillatory properties with Kerr black holes, highlighting observable differences.

Findings

Wormholes exhibit various frequency orderings unlike black holes.

Diverse resonances, including lower-order parametric and forced resonances, are possible in wormholes.

Resonances can occur near the wormhole throat, offering potential observational tests of strong gravity.

Abstract

We study the quasi-periodic oscillations from the accretion disk around rotating traversable wormholes by means of the resonance models. We investigate the linear stability of the circular geodesic orbits in the equatorial plane for a general class of wormhole geometries deriving analytical expressions for the epicyclic frequencies. Since wormholes can often mimic black holes in the astrophysical observations, we analyze the properties of the quasi-circular oscillatory motion in comparison with the Kerr black hole. We demonstrate that wormholes possess distinctive features, which can be observationally significant. It is characteristic for the Kerr black hole that the orbital and the epicyclic frequencies obey a constant ordering in the whole range of the spin parameter. In contrast, for wormhole spacetimes we can have various types of orderings between the frequencies in the different regions of the parametric space. This enables the excitation of much more diverse types of resonances including parametric and forced resonances of lower order, which could lead to stronger observable signals. In addition, for co-rotating orbits the resonances can be excited in a very close neighbourhood of the wormhole throat for a wide range of values of the angular momentum, making wormholes a valuable laboratory for testing strong gravity.