3 papers
gr-qc2025
Extended mass and spheroidal deformation effects on epicyclic frequencies and periapsis shift in quasi-circular orbits
Takahisa Igata
We investigate the effects of extended mass and spheroidal deformation on the periapsis shift of quasi-circular orbits inside a gravitating mass distribution in the Newtonian frame…
gr-qc2025
Gravitational lensing and accretion disk imaging of a Buchdahl dense core
Takahisa Igata, Motoki Omamiuda, Yohsuke Takamori
In this paper, we investigate the gravitational lensing and accretion disk imaging characteristics of a dense core modeled by the Buchdahl spacetime. By imposing the appropriate en…
hep-ph2025
General relativistic effects on photon spectrum emitted from dark matter halos around primordial black holes
Toya Suzuki, Takahisa Igata, Kazunori Kohri +1
We investigate general relativistic effects on the photon spectrum emitted from decaying (or annihilating) particle dark matter in the halo surrounding a primordial black hole. The…