The deflection angle of a gravitational source with global monopole in the strong field limit

TL;DR

This paper studies gravitational lensing around a Schwarzschild black hole with a global monopole, revealing how the monopole parameter affects image positions and magnifications in the strong field limit.

Contribution

It provides a detailed analysis of the influence of a global monopole on gravitational lensing in the strong field regime, highlighting potential observational signatures.

Findings

Angular position and magnification depend on the monopole parameter η.

As η increases, the impact parameter u_m and separation s increase.

The separation s grows rapidly with larger η.

Abstract

We investigate the gravitational lensing effect in the strong field background around the Schwarzschild black hole with extremely small mass and solid deficit angle subject to the global monopole by means of the strong field limit issue. We obtain the angular position and magnification of the relativistic images and show that they relate to the global monopole parameter $\eta$. We discuss that with the increase of parameter $\eta$, the minimum impact parameter $u_{m}$ and angular separation $s$ increase and the relative magnification $r$ decreases. We also find that $s$ grows extremely greatly as the increasing parameter $\eta$ becomes large enough. The effect from the solid deficit angle is the dependence of angular position, angular separation and relative magnification on parameter $\eta$, which may offer a way to characterize some possible distinct signatures of the Schwarzschild black hole with a solid deficit angle associated with global monopole.