934 citations
Counting papers with at most 25 authors, so collaboration author lists do not stand in for the people here.
- The University of TokyoJP492 papers
- Kyoto UniversityJP316 papers
- Centre National de la Recherche ScientifiqueFR275 papers
- Tokyo Institute of TechnologyJP265 papers
- Hiroshima UniversityJP240 papers
- Institut National de Physique Nucléaire et de Physique des ParticulesFR239 papers
- RIKEN Nishina CenterJP216 papers
- High Energy Accelerator Research OrganizationJP213 papers
- RIKENJP205 papers
- Commissariat à l'Énergie Atomique et aux Énergies AlternativesFR201 papers
- Columbia UniversityUS199 papers
- Eötvös Loránd UniversityHU198 papers
25 papers · 2 filters
Primordial black hole formation from massless scalar isocurvature
Chul-Moon Yoo, Tomohiro Harada, Shin'ichi Hirano +2
We numerically study the primordial black hole (PBH) formation by an isocurvature perturbation of a massless scalar field on super Hubble scales in the radiation-dominated universe…
Narrowband searches for continuous and long-duration transient gravitational waves from known pulsars in the LIGO-Virgo third observing run
The LIGO Scientific Collaboration, the Virgo Collaboration, the KAGRA Collaboration +1658
Isolated neutron stars that are asymmetric with respect to their spin axis are possible sources of detectable continuous gravitational waves. This paper presents a fully-coherent s…
The Aretakis constants and instability in general spherically symmetric extremal black hole spacetimes: higher multipole modes, late-time tails, and geometrical meanings
Takuya Katagiri, Masashi Kimura
We study late-time behaviors of massive scalar fields in general static and spherically symmetric extremal black hole spacetimes in arbitrary dimensions. We show the existence of c…
Tests of General Relativity with GWTC-3
The LIGO Scientific Collaboration, the Virgo Collaboration, the KAGRA Collaboration +1682
The ever-increasing number of detections of gravitational waves (GWs) from compact binaries by the Advanced LIGO and Advanced Virgo detectors allows us to perform ever-more sensiti…
Spectral Problems for Quasinormal Modes of Black Holes
Yasuyuki Hatsuda, Masashi Kimura
This is an unconventional review article on spectral problems in black hole perturbation theory. Our purpose is to explain how to apply various known techniques in quantum mechanic…
Complete classification of Friedmann-Lemaître-Robertson-Walker solutions with linear equation of state: parallelly propagated curvature singularities for general geodesics
Tomohiro Harada, Takahisa Igata, Takuma Sato +1
We completely classify the Friedmann-Lemaître-Robertson-Walker solutions with spatial curvature for perfect fluids with linear equation of state , where and $…
All-sky, all-frequency directional search for persistent gravitational-waves from Advanced LIGO's and Advanced Virgo's first three observing runs
The LIGO Scientific Collaboration, the Virgo Collaboration, the KAGRA Collaboration +1627
We present the first results from an all-sky all-frequency (ASAF) search for an anisotropic stochastic gravitational-wave background using the data from the first three observing r…
Revisiting timelike geodesics in the Fisher-Janis-Newman-Winicour-Wyman spacetime
Keisuke Ota, Shinpei Kobayashi, Keisuke Nakashi
We investigate the timelike geodesics and the periapsis precession of orbits in the Fisher-Janis-Newman-Winicour-Wyman spacetime. This spacetime represents the naked singularity sp…
Distinguishing modified gravity with just two tensorial degrees of freedom from general relativity: Black holes, cosmology, and matter coupling
Aya Iyonaga, Tsutomu Kobayashi
We consider spatially covariant modified gravity in which the would-be scalar degree of freedom is made non-dynamical and hence there are just two tensorial degrees of freedom, i.e…
Weyl transverse diffeomorphism invariant theory of symmetric teleparallel gravity
Yu Nakayama
We construct a Weyl transverse diffeomorphism invariant theory of symmetric teleparallel gravity by employing the Weyl compensator formalism. The low-energy dynamics has a single s…
Stars disformally coupled to a shift-symmetric scalar field
Tact Ikeda, Aya Iyonaga, Tsutomu Kobayashi
We investigate static and spherically symmetric stars disformally coupled to a scalar field. The scalar field is assumed to be shift symmetric, and hence the conformal and disforma…
All-sky search for long-duration gravitational-wave bursts in the third Advanced LIGO and Advanced Virgo run
The LIGO Scientific Collaboration, the Virgo Collaboration, the KAGRA Collaboration +1627
After the detection of gravitational waves from compact binary coalescences, the search for transient gravitational-wave signals with less well-defined waveforms for which matched…
All-sky search for short gravitational-wave bursts in the third Advanced LIGO and Advanced Virgo run
The LIGO Scientific Collaboration, the Virgo Collaboration, the KAGRA Collaboration +1630
This paper presents the results of a search for generic short-duration gravitational-wave transients in data from the third observing run of Advanced LIGO and Advanced Virgo. Trans…
Dynamics of inflation with mutually orthogonal vector fields in a closed universe
Tomoaki Murata, Tsutomu Kobayashi
We study the dynamics of a homogeneous, isotropic, and positively curved universe in the presence of a SU(2) gauge field or a triplet of mutually orthogonal vector fields. In the S…
Robustness of particle creation in the formation of a compact object
Kazumasa Okabayashi, Tomohiro Harada, Ken-ichi Nakao
Hawking has predicted that the formation of a black hole by gravitational collapse causes quantum particle creation and the spectrum of the particles is almost thermal. This phenom…
All-sky Search for Continuous Gravitational Waves from Isolated Neutron Stars in the Early O3 LIGO Data
The LIGO Scientific Collaboration, the Virgo Collaboration, the KAGRA Collaboration +1587
We report on an all-sky search for continuous gravitational waves in the frequency band 20-2000\,Hz and with a frequency time derivative in the range of …
Thakurta metric does not describe a cosmological black hole
Tomohiro Harada, Hideki Maeda, Takuma Sato
Recently, the Thakurta metric has been adopted as a model of primordial black holes. We show that the spacetime described by this metric has neither black-hole event horizon nor bl…
Gravitational lensing by two photon spheres in a black-bounce spacetime in strong deflection limits
Naoki Tsukamoto
We investigate gravitational lensing by a primary photon sphere which is a sphere filled with unstable circular light orbits, and by a secondary photon sphere on a wormhole throat…
The isotropic attractor solution of axion-SU(2) inflation: Universal isotropization in Bianchi type-I geometry
Ira Wolfson, Azadeh Maleknejad, Tomoaki Murata +2
SU(2) gauge fields coupled to an axion field can acquire an isotropic background solution during inflation. We study homogeneous but anisotropic inflationary solutions in the prese…
Backreaction of Mass and Angular Momentum Accretion on Black Holes: General Formulation of the Metric Perturbations and Application to the Blandford-Znajek Process
Masashi Kimura, Tomohiro Harada, Atsushi Naruko +1
We study the metric backreaction of mass and angular momentum accretion on black holes. We first develop the formalism of monopole and dipole linear gravitational perturbations aro…
Search for anisotropic gravitational-wave backgrounds using data from Advanced LIGO and Advanced Virgo's first three observing runs
The LIGO Scientific Collaboration, the Virgo Collaboration, the KAGRA Collaboration +1589
We report results from searches for anisotropic stochastic gravitational-wave backgrounds using data from the first three observing runs of the Advanced LIGO and Advanced Virgo det…
Revisiting the Aretakis constants and instability in two-dimensional Anti-de Sitter spacetimes
Takuya Katagiri, Masashi Kimura
We discuss dynamics of massive Klein-Gordon fields in two-dimensional Anti-de Sitter spacetimes (), in particular conserved quantities and non-modal instability on the futur…
Constraints on cosmic strings using data from the third Advanced LIGO-Virgo observing run
The LIGO Scientific Collaboration, the Virgo Collaboration, the KAGRA Collaboration +1586
We search for gravitational-wave signals produced by cosmic strings in the Advanced LIGO and Virgo full O3 data set. Search results are presented for gravitational waves produced b…
Upper Limits on the Isotropic Gravitational-Wave Background from Advanced LIGO's and Advanced Virgo's Third Observing Run
The LIGO Scientific Collaboration, the Virgo Collaboration, the KAGRA Collaboration +1587
We report results of a search for an isotropic gravitational-wave background (GWB) using data from Advanced LIGO's and Advanced Virgo's third observing run (O3) combined with upper…