# Light Deflection by a Rotating Global Monopole Spacetime

## TL;DR

This paper studies how light bends around rotating global monopole and Letelier spacetimes, showing that certain parameters increase deflection, and generalizes previous non-rotating and Kerr results using the Gauss-Bonnet theorem.

## Contribution

It introduces a method to analyze light deflection in rotating monopole spacetimes and extends existing results to include rotation effects.

## Key findings

- Light deflection increases with global monopole parameter.
- Rotation affects the deflection angle in these spacetimes.
- Results generalize known non-rotating and Kerr spacetime deflections.

## Abstract

We investigate the deflection of light by a rotating global monopole spacetime and a rotating Letelier spacetime in the weak deflection approximation. To this end, we apply the Gauss-Bonnet theorem to the corresponding osculating optical geometries and show that the deflection of light increases due to the presence of the global monopole parameter and the string cloud parameter, respectively. The results obtained for the deflection angle in the equatorial plane generalize known results for the corresponding non-rotating global monopole and Letelier spacetimes as well as the Kerr solution.