Thin accretion disks around traversable wormholes

TL;DR

This paper investigates the physical properties and observational signatures of accretion disks around rotating traversable wormholes, comparing them with Kerr black holes to aid in distinguishing these exotic objects.

Contribution

It provides a detailed analysis of accretion disk characteristics and images around Teo class wormholes, including flux, temperature, spectra, and ray-traced images, extending previous studies to wormhole spacetimes.

Findings

Accretion efficiency varies with spin and throat radius.

Distinctive image features differentiate wormholes from black holes.

Maximum luminosity frequency depends on wormhole parameters.

Abstract

In this paper, we aim to investigate various physical properties and characteristics of radiation emerging from the surface of accretion disks, in a rotating traversable axially symmetric wormhole spacetime of the Teo class. We have studied the marginally stable orbits and accretion efficiency graphically, corresponding to different values of dimensionless spin parameter $J/M^2$ ranging from 0.2 to 1.5 and some values of the throat radius $r_0$, in comparison to the Kerr black hole with the same parameter values, and also tabulated the results. The energy flux radiated by the accretion disk $F(r)$, the temperature distribution $T(r)$ and the emission spectra $\nu L(\nu)$ is plotted, corresponding to varying values of the dimensionless spin parameter $J/M^2$ and throat radius $r_0$. Also, the critical frequency at which the luminosity attains its maximum value, for various values of the angular momentum of the wormhole $J/M^2$ and $r_0$ is tabulated. Lastly, we have employed ray-tracing technique, to produce the intensity map of the image of an accretion disk, as observed by an asymptotic observer, under two conditions: firstly when the disk is on the same side as the observer and we have also compared those with the images of an accretion disk in case of Kerr black hole with same parameters. Secondly, the images have been provided when the disk and observer are on opposite sides of the throat. This study may help to detect and distinguish wormhole geometries from other compact objects.