Study of a Tilted Thin Accretion Disk around a Kerr-Taub-NUT black hole

TL;DR

This paper investigates the structure of a tilted thin accretion disk around a Kerr-Taub-NUT black hole, analyzing how gravitomagnetic monopoles influence disk tilt and potentially providing insights into strong gravity and GMM existence.

Contribution

It presents a novel calculation of the radial tilt profile of a thin accretion disk around a Kerr-Taub-NUT black hole, considering the effects of GMM and disk viscosity.

Findings

GMM can cause the disk to align or become more tilted depending on parameters.

The tilt profile depends on viscosity and Kerr parameter values.

Results may help detect GMM effects in astrophysical observations.

Abstract

The accreting collapsed object GRO J1655-40 could contain the gravitomagnetic monopole (GMM), and it was shown to be better described by the Kerr-Taub-NUT (KTN) spacetime instead of the Kerr spacetime. The warped accretion disk has also been observed for the same collapsed object. Motivated by these, we study a tilted thin inner accretion disk around a KTN black hole. Such a tilting could have a significant effect on the X-ray spectral and timing features via the Lense-Thirring effect. Taking into account the contribution from the inner accretion disk for the KTN black hole, here we calculate the radial profile of a tilt angle. Depending on the numerical values of the viscosity of the accreting material and Kerr parameter, GMM tends the angular momentum of the disk to align along the black hole's spin axis, or to make it more tilted. Our solution for the radial profile of the tilted disk around a KTN black hole could be useful to probe the strong gravity regime, and could also give indirect evidence for the existence of GMM in nature.