Motoyuki Saijo

Collapse of differentially rotating supermassive stars: Post black hole formation (2009)

Saijo, Motoyuki, Hawke, Ian

We investigate the collapse of differentially rotating supermassive stars (SMSs) by means of 3+1 hydrodynamic simulations in general relativity. We particularly focus on the onset of collapse to...

DECIGO pathfinder (2009)

Ando, Masaki, Kawamura, Seiji, Sato, Shuichi, Nakamura, Takashi, Tsubono, Kimio, Araya, Akito, ...

DECIGO pathfinder (DPF) is a milestone satellite mission for DECIGO (DECi-hertz Interferometer Gravitational wave Observatory), which is a future space gravitational wave antenna. DECIGO is expected...

Amplification of azimuthal modes with odd wave numbers during dynamical bar-mode growth in rotating stars (2008)

Kojima, Yasufumi, Saijo, Motoyuki

Nonlinear growth of the bar-mode deformation is studied for a differentially rotating star with supercritical rotational energy. In particular, the growth mechanism of some azimuthal modes with odd...

DECIGO pathfinder (2008)

Ando, Masaki, Kawamura, Seiji, Nakamura, Takashi, Tsubono, Kimio, Tanaka, Takahiro, Funaki, Ikkoh, ...

DECIGO pathfinder (DPF) is a milestone satellite mission for DECIGO (DECi-hertz Interferometer Gravitational wave Observatory) which is a future space gravitational wave antenna. DECIGO is expected...

The Japanese space gravitational wave antenna; DECIGO (2008)

Kawamura, Seiji, Ando, Masaki, Nakamura, Takashi, Tsubono, Kimio, Tanaka, Takahiro, Funaki, Ikkoh, ...

DECi-hertz Interferometer Gravitational wave Observatory (DECIGO) is the future Japanese space gravitational wave antenna. DECIGO is expected to open a new window of observation for gravitational...

Faraday resonance in dynamical bar instability of differentially rotating stars (2008)

Saijo, Motoyuki, Kojima, Yasufumi

We investigate the nonlinear behaviour of the dynamically unstable rotating star for the bar mode by three-dimensional hydrodynamics in Newtonian gravity. We find that an oscillation along the...

Viscosity driven instability in rotating relativistic stars (2006)

Saijo, Motoyuki, Gourgoulhon, Eric

We investigate the viscosity driven instability in rotating relativistic stars by means of an iterative approach. We focus on polytropic rotating equilibrium stars and impose a m=2 perturbation in...

Gravitational waves from a dust disk around a Schwarzschild black hole (2006)

Sotani, Hajime, Saijo, Motoyuki

We investigate gravitational waves from a dust disk around a Schwarzschild black hole to focus on whether we can extract any of its physical properties from a direct detection of gravitational waves....

Viscosity driven instability in rotating relativistic stars (2006)

Saijo, Motoyuki, Gourgoulhon, Eric

We investigate the viscosity driven instability in rotating relativistic stars by means of an iterative approach. We focus on polytropic rotating equilibrium stars and impose an m=2 perturbationin...

Low T/|W| dynamical instability in differentially rotating stars: diagnosis with canonical angular momentum (2006)

Saijo, Motoyuki, Yoshida, Shin'ichirou

We study the nature of non-axisymmetric dynamical instabilities in differentially rotating stars with both linear eigenmode analysis and hydrodynamic simulations in Newtonian gravity. We especially...

Low T/|W| dynamical instabilities in differentially rotating stars: Diagnosis with canonical angular momentum (2006)

Saijo, Motoyuki, Yoshida, Shin'ichirou

We study the nature of non-axisymmetric dynamical instabilities in differentially rotating stars with both linear eigenmode analysis and hydrodynamic simulations in Newtonian gravity. We especially...

Gravitational waves from a dust disk around a Schwarzschild black hole (2005)

Sotani, Hajime, Saijo, Motoyuki

We investigate gravitational waves from a dust disk around a Schwarzschild black hole to focus on whether we can extract any of its physical properties from a direct detection of gravitational waves....

Dynamical bar instability in a relativistic rotational core collapse (2005)

Saijo, Motoyuki

We investigate the rotational core collapse of a rapidly rotating relativistic star by means of a 3+1 hydrodynamical simulation in conformally flat spacetime of general relativity. We concentrate our...

Low T/|W| dynamical instability in differentially rotating stars: Diagnosis with canonical angular momentum (2005)

Saijo, Motoyuki, Yoshida, Shin'ichirou

We study the nature of non-axisymmetric dynamical instabilities in differentially rotating stars with both linear eigenmode analysis and hydrodynamic simulations in Newtonian gravity. We especially...

Dynamical bar instability in a relativistic rotational core collapse (2005)

Saijo, Motoyuki

We investigate the rotational core collapse of a rapidly rotating relativistic star by means of a 3+1 hydrodynamical simulations in conformally flat spacetime of general relativity. We concentrate...

Dynamical One-Armed Spiral Instability in Differentially Rotating Stars (2005)

Saijo, Motoyuki, Yoshida, Shin'ichirou

We investigate the dynamical one-armed spiral instability in differentially rotating stars with both eigenmode analysis and hydrodynamic simulations in Newtonian gravity. We find that the one-armed...

The Collapse of Differentially Rotating Supermassive Stars: Conformally Flat Simulations (2004)

Saijo, Motoyuki

We investigate the gravitational collapse of rapidly rotating relativistic supermassive stars by means of a 3+1 hydrodynamical simulations in conformally flat spacetime of general relativity. We...

The collapse of differentially rotating supermassive stars: conformally flat simulations (2004)

Saijo, Motoyuki

We investigate the gravitational collapse of rapidly rotating relativistic supermassive stars by means of a 3+1 hydrodynamical simulations in conformally flat spacetime of general relativity. We...

One-Armed Spiral Instability in Differentially Rotating Stars (2003)

Saijo, Motoyuki, Baumgarte, Thomas W., Shapiro, Stuart L.

We investigate the dynamical instability of the one-armed spiral m=1 mode in differentially rotating stars by means of 3+1 hydrodynamical simulations in Newtonian gravitation. We find that both a...

One-armed spiral instability in differentially rotating stars (2003)

Saijo, Motoyuki, Baumgarte, Thomas W., Shapiro, Stuart L.

We investigate the dynamical instability of the one-armed spiral m=1 mode in differentially rotating stars by means of 3+1 hydrodynamical simulations in Newtonian gravitation. We find that both a...

Collapse of a Rotating Supermassive Star to a Supermassive Black Hole: Post-Newtonian Simulations (2002)

Saijo, Motoyuki, Baumgarte, Thomas W., Shapiro, Stuart L., Shibata, Masaru

We study the gravitational collapse of a rotating supermassive star (SMS) by means of a (3+1) hydrodynamical simulation in a post-Newtonian (PN) approxi- mation of general relativity. This problem is...

Collapse of a rotating supermassive star to a supermassive black hole: post-Newtonian simulations (2002)

Saijo, Motoyuki, Baumgarte, Thomas W., Shapiro, Stuart L., Shibata, Masaru

We study the gravitational collapse of a rotating supermassive star (SMS) by means of a (3+1) hydrodynamical simulation in a post-Newtonian (PN) approxi- mation of general relativity. This problem is...

Gravitational waves from a spinning particle scattered by a relativistic star: axial mode case (2001)

Tominaga, Kazuhiro, Saijo, Motoyuki, Maeda, Kei-ichi

We use a perturbation method to study gravitational waves from a spinning test particle scattered by a relativistic star. The present analysis is restricted to axial modes. By calculating the energy...

Possible direct method to determine the radius of a star from the spectrum of gravitational wave signals. II. Spectra for various cases (2001)

Saijo, Motoyuki, Nakamura, Takashi

We compute the spectrum and the waveform of gravitational waves generated by the inspiral of a disk or a spherical like dust body into a Kerr black hole. We investigate the effect of the radius R of...

Dynamical Bar Instability in Relativistic Rotating Stars (2001)

Saijo, Motoyuki, Shibata, Masaru, Baumgarte, Thomas W., Shapiro, Stuart L.

We study by computational means the dynamical stability against bar-mode deformation of rapidly and differentially rotating stars in a post-Newtonian approximation of general relativity. We vary the...

Dynamical bar instability in rotating stars: effect of general relativity (2001)

Saijo, Motoyuki, Shibata, Masaru, Baumgarte, Thomas W., Shapiro, Stuart L.

We study the dynamical stability against bar-mode deformation of rapidly and differentially rotating stars in the first post-Newtonian approximation of general relativity. We vary the compaction of...

Possible direct method to determine the radius of a star from the spectrum of gravitational wave signals II : Spectra for various cases (2000)

Saijo, Motoyuki, Nakamura, Takashi

We compute the spectrum and the waveform of gravitational waves generated by the inspiral of a disk or a spherical like dust body into a Kerr black hole. We investigate the effect of the radius R of...

Dynamical Bar Instability in Rotating Stars: Effect of General Relativity (2000)

Saijo, Motoyuki, Shibata, Masaru, Baumgarte, Thomas W., Shapiro, Stuart L.

We study the dynamical stability against bar-mode deformation of rapidly and differentially rotating stars in the first post-Newtonian approximation of general relativity. We vary the compaction of...

Gravitational waves from a spinning particle scattered by a relativistic star: Axial mode case (2000)

Tominaga, Kazuhiro, Saijo, Motoyuki, Maeda, Kei-ichi

We study gravitational waves from a spinning test particle scattered by a relativistic star using a perturbation method. The present analysis is restricted to axial modes. By calculating the energy...

Possible direct method to determine the radius of a star from the spectrum of gravitational wave signals (2000)

Saijo, Motoyuki, Nakamura, Takashi

We computed the spectrum of gravitational waves from a dust disk star of radius R inspiraling into a Kerr black hole of mass M and specific angular momentum a. We found that when R is much larger...

Gravitational waves from a test particle scattered by a neutron star: Axial mode case (1999)

Tominaga, Kazuhiro, Saijo, Motoyuki, Maeda, Kei-ichi

Using a metric perturbation method, we study gravitational waves from a test particle scattered by a spherically symmetric relativistic star. We calculate the energy spectrum and the waveform of...

Gravitational Waves in Brans-Dicke Theory : Analysis by Test Particles around a Kerr Black Hole (1996)

Saijo, Motoyuki, Shinkai, Hisa-aki, Maeda, Kei-ichi

Analyzing test particles falling into a Kerr black hole, we study gravitational waves in Brans-Dicke theory of gravity. First we consider a test particle plunging with a constant azimuthal angle into...