Deflection Angle in the Strong Deflection Limit and Quasinormal Modes in Stationary Axisymmetric Spacetimes

Takahisa Igata

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arXiv · 2505.01848

Deflection Angle in the Strong Deflection Limit and Quasinormal Modes in Stationary Axisymmetric Spacetimes

Takahisa Igata

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Abstract

We derive a coordinate-invariant expression for the photon deflection angle in the strong deflection limit (SDL) of stationary axisymmetric spacetimes. The key logarithmic-divergence coefficient is shown to depend only on quantities locally measurable by a zero-angular-momentum observer -- curvature scalars, the circumferential radius, and the proper angular velocity. The same coefficient governs the damping rate of quasinormal modes (QNMs) in the eikonal limit, establishing a curvature-based, model-independent connection between QNMs and lensing in the SDL near rotating compact objects.

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BibTeX RIS

Takahisa Igata. 2025-05-03. Deflection Angle in the Strong Deflection Limit and Quasinormal Modes in Stationary Axisymmetric Spacetimes. https://arxiv.org/abs/2505.01848

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