Takahisa Igata Takahisa Igata

Assistant Professor, Faculty of Science, Gakushuin University *Profile is at the time of the award.

2026HagukumuScience & Engineering(hagukumu)

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Research topics: Generalization of the local geometric description of the light deflection angle in the strong deflection limit

Keyword

Summary: This study aims to clarify, on theoretical grounds, how the spacetime structure in the strong-gravity region surrounding black hole candidates is reflected in observable quantities such as the deflection angle of light and the damping rates of gravitational-wave oscillations. With a particular focus on the regime of extreme light bending, it develops a framework for a unified understanding of these observables by relating them to spacetime curvature. In doing so, it provides a new theoretical approach for distinguishing black holes from compact objects that closely mimic them, and for inferring the nature of such candidates and the properties of strong gravitational fields from observations of black hole shadows and gravitational waves.

Message

To what extent can we determine the true nature of black hole candidates through observation? This fundamental question connects observation and theory in our effort to understand the most extreme gravitational fields in the universe. By focusing on the strong bending of light near compact objects, I aim to clarify how observable features of light reflect the underlying structure of spacetime, thereby providing new insights into the physics of strong gravitational fields.