output
20222025
most citedVanishing Love of Black Holes in General Relativity: From Spacetime Conformal Symmetry of a Two-dimensional Reduced Geometry

40 citations

researchers with a paper here

Counting papers with at most 25 authors, so collaboration author lists do not stand in for the people here.

collaborating institutions

7 papers

gr-qc2025

Probing higher curvature gravity via ringdown with overtones

Keisuke Nakashi, Masashi Kimura, Hayato Motohashi +1

We investigate metric perturbations of a spherically symmetric black hole in higher curvature gravity. We show that higher curvature corrections deform the near-horizon region of t…

gr-qc2025★ 2 cited

Shadow formation in gravitational collapse: Redshift and blueshift by spacetime dynamics

Yasutaka Koga, Nobuyuki Asaka, Masashi Kimura +1

A black hole illuminated by a background light source is observed as a black hole shadow. For a black hole formed by gravitational collapse of a transmissive object, redshift of li…

gr-qc2024★ 23 cited

Parametrized Black Hole Quasinormal Ringdown Formalism for Higher Overtones

Shin'ichi Hirano, Masashi Kimura, Masahide Yamaguchi +1

We investigate the parametrized black hole quasinormal ringdown formalism, which is a robust framework used to analyze quasinormal modes in systems that closely resemble general re…

gr-qc2023★ 8 cited

Black hole ringdown from physically sensible initial value problem in higher-order scalar-tensor theories

Keisuke Nakashi, Masashi Kimura, Hayato Motohashi +1

We study odd-parity perturbations about static and spherically symmetric black hole solutions with a linearly time-dependent scalar field in higher-order scalar-tensor theories. In…

gr-qc2022★ 40 cited

Vanishing Love of Black Holes in General Relativity: From Spacetime Conformal Symmetry of a Two-dimensional Reduced Geometry

Takuya Katagiri, Masashi Kimura, Hiroyuki Nakano +1

We study the underlying structure of the vanishing of the Love numbers of both Schwarzschild and Kerr black holes in terms of spacetime conformal symmetry in a unified manner for t…

gr-qc2022★ 12 cited

Black hole perturbations in higher-order scalar-tensor theories: initial value problem and dynamical stability

Keisuke Nakashi, Masashi Kimura, Hayato Motohashi +1

We propose a physically sensible formulation of initial value problem for black hole perturbations in higher-order scalar-tensor theories. As a first application, we study monopole…

gr-qc2022★ 34 cited

Dynamical photon sphere and time evolving shadow around black holes with temporal accretion

Yasutaka Koga, Nobuyuki Asaka, Masashi Kimura +1

A photon sphere is known as the geometrical structure shaping a black hole shadow. The mechanism is well understood for static or stationary black hole spacetimes such as the Schwa…