arXiv subjects

Masaru Shibata

Publications and source records attributed to Masaru Shibata.

255 records · Page 15Linked to original sources

arXiv1996

Gravitational waves from a spinning particle in circular orbits around a rotating black hole

Using the Teukolsky and Sasaki-Nakamura formalisms for the perterbations around a Kerr black hole, we calculate the energy flux of gravitational waves induced by a {\it spinning} particle of mass $μ$ and spin $S$ moving in circular orbits near the equatorial plain of a rotating black hole of mass $M (\gg μ)$ and spin $Ma$. The calculations are performed by using the recently developed post-Newtonian expansion technique of the Teukolsky equation. To evaluate the source terms of perturbations caused by a {\it spinning} particle, we used the equations of motion of a spinning particle derived by Papapetrou and the energy momentum tensor of a spinning particle derived by Dixon. We present the post-Newtonian formula of the gravitational wave luminosity up to the order $(v/c)^5$ beyond the quadrupole formula including the linear order of particle spin. The results obtained in this paper will be an important guideline to the post-Newtonian calculation of the inspiral of two spinning compact objects.

gr-qc↗

arXiv1995

Hubble Parameter in Void Universe

We investigate the distance-redshift relation in the simple void model. As discussed by Moffat and Tatarski, if the observer stays at the center of the void, the observed Hubble parameter is not so different from the background Hubble parameter. However, if the position of observer is off center of the void, we must consider the peculiar velocity correction which is measured by the observed dipole anisotropy of cosmic microwave background. This peculiar velocity correction for the redshift is crucial to determine the Hubble parameter and we shall discuss this effect. Further the results of Turner et al by the N-body simulation will be also considered.

astro-ph↗

arXiv1994

Gravitational Waves from a Particle Orbiting Around a Rotating Black Holes: Post-Newtonian Expansion

Using the Teukolsky and Sasaki-Nakamura equations for the gravitational perturbation of the Kerr spacetime, we calculate the post-Newtonian expansion of the energy and angular momentum luminosities of gravitational waves from a test particle orbiting around a rotating black hole up through ${\rm P^{5/2}N}$ order beyond the quadrupole formula. We apply a method recently developed by Sasaki to the case of a rotating black hole. We take into account a small inclination of the orbital plane to the lowest order of the Carter constant. The result to $ P^{3/2}N}$ order is in agreement with a similar calculation by Poisson as well as with the standard post-Newtonian calculation by Kidder et al. Using our result, we calculate the integrated phase of gravitational waves from a neutron star-neutron star binary and a black hole-neutron star binary during their inspiral stage. We find that, in both cases, spin-dependent terms in the P$^2$N and P$^{5/2}$N corrections are important to construct effective template waveforms which will be used for future laser-interferometric gravitational wave detectors.

gr-qc↗