Gravitomagnetic bending angle of light with finite-distance corrections in stationary axisymmetric spacetimes
By T. Ono, Asahi Ishihara, H. Asada. 2017
133 citations recorded by the source corpus.
By using the Gauss-Bonnet theorem, the bending angle of light in a static, spherically symmetric and asymptotically flat spacetime has been recently discussed, especially by taking account of the finite distance from a lens object to a light source and a receiver [Ishihara, Suzuki, Ono, Asada, Phys. Rev. D 95, 044017 (2017)]. We discuss a possible extension of the method of calculating the bending angle of light to stationary, axisymmetric and asymptotically flat spacetimes. For this purpose, we consider the light rays on the equatorial plane in the axisymmetric spacetime. We introduce a spatial metric to define the bending angle of light in the finite-distance situation. We show that the proposed bending angle of light is coordinate-invariant by using the Gauss-Bonnet theorem. The non-vanishing geodesic curvature of the photon orbit with the spatial metric is caused in gravitomagnetism, even though the light ray in the four-dimensional spacetime follows the null geodesic. Finally, we consider Kerr spacetime as an example in order to examine how the bending angle of light is computed by the present method. The finite-distance correction to the gravitomagnetic deflection angle due to the Sun's spin is around a pico-arcsecond level. The finite-distance corrections for Sgr A$^{\ast}$ also are estimated to be very small. Therefore, the gravitomagnetic finite-distance corrections for these objects are unlikely to be observed with present technology.
Subfields: Astronomy and Astrophysics, Ocean Engineering
View Paper: https://www.semanticscholar.org/paper/d068dda5affc3d70c2f8d74499c5b78936cd9d2b
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Citations in the corpus
- Shadow cast and deflection angle of Kerr-Newman-Kasuya spacetime (2018, methodology): “As a consequence of the GBT, the result obtained has a global effect.”
- Gravitational lensing by black holes in the 4D Einstein-Gauss-Bonnet gravity (2020, background): “[79] for the stationary and axisymmetric black holes.”