Zobrazeno 1 - 10
of 71
pro vyhledávání: '"Takahisa Igata"'
Autor:
Yohsuke Takamori, Takahisa Igata
We consider the periapsis shifts in dark matter distribution with a dense core. We model the dark matter distribution as an isotropic gas sphere, the Emden polytropic sphere of index 5 in general relativity. This model has a parameter range where all
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::f7d1f7f068fdca81f247b64f38b198c6
http://arxiv.org/abs/2202.03114
http://arxiv.org/abs/2202.03114
Autor:
Kota Ogasawara, Takahisa Igata
We consider necessary and sufficient conditions for photons emitted from an arbitrary spacetime position of the extremal Kerr black hole to escape to infinity. The radial equation of motion determines the necessary conditions for photons emitted from
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::b82ae8a206fd9d3259122289193f3286
http://arxiv.org/abs/2111.03243
http://arxiv.org/abs/2111.03243
Autor:
Shinya Tomizawa, Takahisa Igata
Publikováno v:
Physical Review
Reducing motion of particles to a two-dimensional potential problem, we show that there are stable circular orbits around a squashed Kaluza-Klein black hole with a spherical horizon and multi-Kaluza-Klein black holes with two spherical horizons in fi
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::09ac7b67868a5fc0b15d23df5fd6f275
http://repo.scoap3.org/api
http://repo.scoap3.org/api
Publikováno v:
Classical and Quantum Gravity. 39:145008
We completely classify the Friedmann-Lema\^{i}tre-Robertson-Walker solutions with spatial curvature $K=0,\pm 1$ for perfect fluids with linear equation of state $p=w\rho $, where $\rho$ and $p$ are the energy density and pressure, without assuming an
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::5da2eb1264ca76c57cce7769c1251241
https://doi.org/10.1088/1361-6382/ac776e
https://doi.org/10.1088/1361-6382/ac776e
Autor:
Takahisa Igata
Euler's three-body problem is the problem of solving for the motion of a particle moving in a Newtonian potential generated by two point sources fixed in space. This system is integrable in the Liouville sense. We consider the Euler problem with the
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::257d3102b3dc81f46cf30179612d0da7
http://arxiv.org/abs/2102.09992
http://arxiv.org/abs/2102.09992
Autor:
Shinya Tomizawa, Takahisa Igata
We consider the motion of massive and massless particles in a five-dimensional spacetime with a compactified extra-dimensional space where a black hole is localized, i.e., a caged black hole spacetime. We show the existence of circular orbits and rev
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::8d6736611525ef657b7bc54952aa147f
http://arxiv.org/abs/2102.00800
http://arxiv.org/abs/2102.00800
Publikováno v:
Physical Review D. 103
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 phot
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::a69ff5906770441b231c8dbfa74b514f
https://doi.org/10.1103/physrevd.103.044003
https://doi.org/10.1103/physrevd.103.044003
We consider a situation where a light source orbiting the innermost stable circular orbit (ISCO) of the Kerr black hole is gently falling from the marginally stable orbit due to an infinitesimal perturbation. Assuming that the light source emits phot
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::972d7cccb2979b7687ae6b3382d8a3ef
Autor:
Shinya Tomizawa, Takahisa Igata
Publikováno v:
Physical Review
In contrast to five-dimensional Schwarzschild-Tangherlini and Myers-Perry backgrounds, we show that there are stable bound orbits of massive/massless particles in five-dimensional black lens backgrounds, in particular, the supersymmetric black lens w
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::8cde0e92abc8ffbe883bc38e0b08a3cb
https://doi.org/10.1103/physrevd.102.124079
https://doi.org/10.1103/physrevd.102.124079
Autor:
Shinya Tomizawa, Takahisa Igata
Publikováno v:
Physical Review
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-Perry
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::dcfddb62cd2fbff53b8890c363c7ae9e
https://doi.org/10.1103/physrevd.102.084003
https://doi.org/10.1103/physrevd.102.084003