251 citations · 2.2k across the 40 of their papers we have counts for
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Gravitational lensing by using the 0th order of affine perturbation series of the deflection angle of a ray near a photon sphere
Naoki Tsukamoto
The 0th order of affine perturbation series of the deflection angle of a ray near a photon sphere is more accurate than a deflection angle in a strong deflection limit, which is us…
Affine perturbation series of the deflection angle of a ray near the photon sphere of a Reissner-Nordström black hole
Naoki Tsukamoto
We investigate the affine perturbation series of the deflection angle of a ray near the photon sphere of an extreme Reissner-Nordström black hole. We compare the 0th and 1st orders…
Is there a trade-off relation between efficiency and power in a collisional Penrose process in an extreme Reissner-Nordström spacetime?
Naoki Tsukamoto
We investigate the power of a collisional Penrose process with an unbound energy extraction from an extreme Reissner-Nordström black hole. This process takes infinite time in a tim…
Retrolensing by two photon spheres of a black-bounce spacetime
Naoki Tsukamoto
We investigate retrolensing by two photon spheres in a novel black-bounce spacetime suggested by Lobo et al. which can correspond to a Schwarzschild black hole, a regular black hol…