2024/01/23 by Zonghai Li, Li, Zonghai
Physics and Astronomy · #Astrophysical Phenomena and Observations #High-Energy Particle Collisions Research #Astrophysics and Cosmic Phenomena
paper · pdf · doi:10.48550/arxiv.2401.12525
In this paper, we introduce a method for calculating the deflection angle in the weak-field approximation, applicable to both null and timelike rays. By combining the trajectory equation Z(u)=(du/dϕ)2 and the `straight line' u(φ)=sinφ/b, we introduce a new function Φ(φ). The deflection angle can then be expressed as δ=Φ(0)+Φ(π)-π, which directly depends on the impact parameter rather than the closest approach distance. This method offers a convenient and straightforward approach to calculations, avoiding the complexities of integration or iterative procedures. As an illustrative application, we compute the deflection angle for charged particle in the Kerr-Newman spacetime.