Continuing work initiated in an earlier publication [Torigoe et al. Phys. Rev. Lett. {\bf 102}, 251101 (2009)], gravitational wave forms for a three-body system in Lagrange's orbit are considered...
Effects of Mutual Transits by Extrasolar Planet-Companion Systems on Light Curves (2009)
We consider the effects of mutual transits by extrasolar planet-companion systems (in a true binary or a planet-satellite system) on light curves. We show that induced changes in light curves depend...
Gravitational waveforms for 2- and 3-body gravitating systems (2009)
Torigoe, Yuji, Hattori, Keisuke, Asada, Hideki
Different numbers of self-gravitating particles (in different types of periodic motion) are most likely to generate very different shapes of gravitational waves, some of which, however, can be...
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...
As an extension of four point mass lenses at the vertices of a rhombus, we present five point mass lenses at the center and vertices of a diamond, which constitute, for a source behind the center, a...
This paper makes the first systematic attempt to determine using perturbation theory the positions of images by gravitational lensing due to arbitrary number of coplanar masses without any symmetry...
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...
Note on Inversion Formula to Determine Binary Elements by Astrometry (2008)
Simplified solutions to determine binary elements by astrometry were obtained in terms of elementary functions (Asada et al. 2004), and therefore require neither iterative nor numerical methods. In...
Back- and Front-Interface Trap Densities Evaluation and Stress Effect of Poly-Si TFT (2008)
TAKATORI, Kenichi, ASADA, Hideki, KANEKO, Setsuo
The polycrystalline silicon (poly-Si) TFT has two insulator interfaces between the polycrystalline silicon and front and back insulators. These interfaces have trap states, which affect the...
Post-Newtonian Hydrodynamic Equations Using the (3+1) Formalism in General Relativity (2007)
Hideki Asada, Masaru Shibata, Toshifumi Futamase
Using the (3+1) formalism in general relativity, we perform the post-Newtonian(PN) approximation to clarify what sort of gauge condition is suitable for numerical analysis of coalescing compact...
Gravitational time delay of light for various models of modified gravity (2007)
We reexamined the gravitational time delay of light, allowing for various models of modified gravity. We clarify the dependence of the time delay (and induced frequency shift) on modified gravity...
Choreographic solution to the general relativistic three-body problem (2007)
Imai, Tatsunori, Chiba, Takamasa, Asada, Hideki
We revisit the three-body problem in the framework of general relativity. The Newtonian N-body problem admits choreographic solutions, where a solution is called choreographic if every massive...
Can N-body systems generate periodic gravitational waves? (2006)
Chiba, Takamasa, Imai, Tatsunori, Asada, Hideki
None of N-body gravitating systems have been considered to emit periodic gravitational waves because of their chaotic orbits when N=3 (or more). We employ a figure-eight orbit as a specific model for...
Simplified solution to determination of a binary orbit (2006)
Asada, Hideki, Akasaka, Toshio, Kudoh, Kazuya
We present a simplified solution to orbit determination of a binary system from astrometric observations. An exact solution was found by Asada, Akasaka and Kasai by assuming no observational errors....
An exact solution to determination of an open orbit (2006)
We present an exact solution of the equations for orbit determination of a two body system in a hyperbolic or parabolic motion. In solving this problem, we extend the method employed by Asada,...
Toward a No-Go Theorem for an Accelerating Universe through a Nonlinear Backreaction (2006)
Kasai, Masumi, Asada, Hideki, Futamase, Toshifumi
The backreaction of nonlinear inhomogeneities to the cosmic expansion is re-analyzed in the framework of general relativity. Apparent discrepancies regarding the effect of the nonlinear backreaction,...
Effects of a deformation of a star on the gravitational lensing (2004)
We study analytically a gravitational lens due to a deformed star, which is modeled by using a monopole and a quadrupole moment. Positions of the images are discussed for a source on the principal...
Inversion formula for determining parameters of an astrometric binary (2004)
Asada, Hideki, Akasaka, Toshio, Kasai, Masumi
It is believed that some numerical technique must be employed for the determination of the system parameters of a visual binary or a star with a planet because the relevant equations are not only...
We study the effect of the core radius of an isothermal ellipsoidal gravitational lens on the caustics and the critical curves. We derive an analytic expression of the caustics for an isothermal...
Euclidean Algorithm for a Gravitational Lens in a Polynomial Equation (2004)
Asada, Hideki, Kasai, Taketoshi, Kasai, Masumi
The Euclidean algorithm in algebra is applied to a class of gravitational lenses for which the lens equation consists of any set of coupled polynomial equations in the image position. In general,...
Comments on "Measuring the Gravity Speed by VLBI" (2003)
Einstein gravity with extra dimensions or alternative gravity theories might suggest that the gravity propagation speed can be different from the light speed. Such a difference may play a vital role...
COMMENTS ON "MEASURING THE GRAVITY SPEED BY VLBI" (2003)
Einstein gravity with extra dimensions or alternative gravity theories might suggest that the gravity propagation speed can be different from the light speed. Such a difference may play a vital role...
COMMENTS ON "MEASURING THE GRAVITY SPEED BY VLBI" (2003)
Einstein gravity with extra dimensions or alternative gravity theories might suggest that the gravity propagation speed can be different from the light speed. Such a difference may play a vital role...
A Parametric Representation of Critical Curves and Caustics for a Binary Gravitational Lens (2003)
We find a simple expression for critical curves of a binary gravitational lens. On the basis of this, we present a parametric representation of such curves. The caustics can also be expressed with...
Separability of Rotational Effects on a Gravitational Lens (2003)
Asada, Hideki, Kasai, Masumi, Yamamoto, Tatsuya
We derive the deflection angle up to $O(m^2a)$ due to a Kerr gravitational lens with mass $m$ and specific angular momentum $a$. It is known that at the linear order in $m$ and $a$ the Kerr lens is...
COMMENTS ON "MEASURING THE GRAVITY SPEED BY VLBI" (2003)
Einstein gravity with extra dimensions or alternative gravity theories might suggest that the gravity propagation speed can be different from the light speed. Such a difference may play a vital role...
COMMENTS ON "MEASURING THE GRAVITY SPEED BY VLBI" (2003)
Einstein gravity with extra dimensions or alternative gravity theories might suggest that the gravity propagation speed can be different from the light speed. Such a difference may play a vital role...
Images for an Isothermal Ellipsoidal Gravitational Lens from a Single Real Algebraic Equation (2002)
Asada, Hideki, Hamana, Takashi, Kasai, Masumi
We present explicit expressions for the lens equation for a cored isothermal ellipsoidal gravitational lens as a single real sixth-order algebraic equation in two approaches; 2-dimensional Cartesian...
The Light-cone Effect on the Shapiro Time Delay (2002)
We investigate the light-cone effect on the Shapiro time delay. The extra time delay caused by Jupiter on the 8th of September 2002 can be measured by advanced VLBI (very long baseline...
Images for a Binary Gravitational Lens from a Single Real Algebraic Equation (2002)
It is shown that the lens equation for a binary gravitational lens being a set of two coupled real fifth-order algebraic equations (equivalent to a single complex equation of the same order) can be...
Perturbative approach to the astrometric microlensing due to an extrasolar planet (2002)
We have developed a perturbative approach to microlensing due to an extrasolar planetary lens. In particular, we have found analytic formulae for triple images. We have used the formulae to...
Itoh, Yousuke, Futamase, Toshifumi, Asada, Hideki
We study the equation of motion appropriate to an inspiralling binary star system whose constituent stars have strong internal gravity. We use the post-Newtonian approximation with the strong field...
Do relativistic corrections affect microlensing amplification? (2000)
Ebina, Junya, Osuga, Takeaki, Asada, Hideki, Kasai, Masumi
Studies of gravitational microlensing are usually based on the lens equation, which is valid only to first order in the gravitational constant $G$. However, the amplification factor of microlensing...
Lagrangian description of fluid flow with pressure in relativistic cosmology (2000)
The Lagrangian description of fluid flow in relativistic cosmology is extended to the case of flow accelerated by pressure. In the description, the entropy and the vorticity are obtained exactly for...
Can we see a rotating gravitational lens? (2000)
It is known that the rotation of a gravitational lens affects properties of images. We consider an inverse problem: If the lens is dark, can we infer its rotation from the observed images? We find...
Itoh, Yousuke, Futamase, Toshifumi, Asada, Hideki
We derive the equation of motion for the relativistic compact binaries in the post-Newtonian approximation taking explicitly their strong internal gravity into account. For this purpose we adopt the...
Distances in Inhomogeneous Cosmological Models (1999)
Tomita, Kenji, Asada, Hideki, Hamana, Takashi
Distances play important roles in cosmological observations, especially in gravitational lens systems, but there is a problem in determining distances because they are defined in terms of light...
Lagrangian description of the fluid flow with vorticity in the relativistic cosmology (1999)
We develop the Lagrangian perturbation theory in the general relativistic cosmology, which enables us to take into account the vortical effect of the dust matter. Under the Lagrangian representation...
Taniguchi, Keisuke, Asada, Hideki, Shibata, Masaru
First post-Newtonian (1PN) hydrostatic equations for an irrotational fluid which have been recently derived are solved for an incompressible star. The 1PN configurations are expressed as a...
Post-Newtonian Approximation (1998)
Asada, Hideki, Futamase, Toshifumi
We discuss various aspects of the post-Newtonian approximation in general relativity. After presenting the foundation based on the Newtonian limit, we use the (3+1) formalism to formulate the...
Formulation for the internal motion of quasi-equilibrium configurations in general relativity (1998)
We present a formulation for the internal motion of equilibrium configurations with a rotational Killing vector in general relativity. As an approximation, this formulation is applicable to...
Observation of Gravitational Lensing in the Clumpy Universe (1998)
We discuss how inhomogeneities of the universe affect observations of the gravitational lensing; (1) the bending angle, (2) the lensing statistics and (3) the time delay. In order to take account of...
Propagation of gravitational waves from slow motion sources in a Coulomb type potential (1997)
Asada, Hideki, Futamase, Toshifumi
We consider the propagation of gravitational waves generated by slow motion sources in Coulomb type potential due to the mass of the source. Then, the formula for gravitational waveform including...
Critical Lines in Gravitational Lenses and the Determination of Cosmological Parameters (1996)
We investigate the cosmological test recently proposed by B. Fort, Y. Mellier and M. Dantel-Fort (FMD), where the observed location of the critical line in gravitational lensing is used to determine...
Asada, Hideki, Shibata, Masaru
We present a formalism to obtain equilibrium configurations of uniformly rotating fluid in the second post-Newtonian approximation of general relativity. In our formalism, we need to solve 29 Poisson...
Post-Newtonian Hydrodynamic Equations Using the (3+1) Formalism in General Relativity (1996)
Asada, Hideki, Shibata, Masaru, Futamase, Toshifumi
Using the (3+1) formalism in general relativity, we perform the post-Newtonian(PN) approximation to clarify what sort of gauge condition is suitable for numerical analysis of coalescing compact...