We consider necessary and sufficient conditions for photons emitted from the vicinity of a Kerr black hole horizon to escape to infinity. The radial equation of motion determines necessary conditions for photons to reach infinity, and the polar an...
Koga, Y.   Igata, T.   Nakashi, K.   
Physical Review D 103(4) 2021年2月 [査読有り]
We investigate photon surfaces and their stability in a less symmetric spacetime, a general static warped product with a warping function acting on a Riemannian submanifold of codimension two. We find a one-dimensional pseudopotential that gives p...
In contrast to five-dimensional Schwarzschild-Tangherlini and Myers-Perry backgrounds, we show that there are stable bound orbits of massive and massless particles in five-dimensional black lens backgrounds, in particular, the supersymmetric black...
We consider the dynamics of particles, particularly focusing on circular orbits in the higher-dimensional Majumdar-Papapetrou (MP) spacetimes with two equal mass black holes. It is widely known that in the 5D Schwarzschild-Tangherlini and Myers-Pe...
We consider test particle motion in a gravitational field generated by a homogeneous circular ring placed in n-dimensional Euclidean space. We observe that there exist no stable stationary orbits in n=6,7,…,10 but exist in n=3, 4, 5 and clarify th...
Journal of Physics: Conference Series 314 012113-012113 2011年9月 [査読有り]
We study stable bound orbits of a free particle around a black ring. Unlike the higher-dimensional black hole case, we find that there exist stable bound orbits in toroidal spiral shape near the ring axis and stable circular orbits on the axis. In...