arXiv subjects

Shugo Michikoshi

Publications and source records attributed to Shugo Michikoshi.

20 records · Page 2Linked to original sources

arXiv2005

Scattering of Gravitational Waves by the Weak Gravitational Fields of Lens Objects

We consider the scattering of the gravitational waves by the weak gravitational fields of lens objects. We obtain the scattered gravitational waveform by treating the gravitational potential of the lens to first order, i.e. using the Born approximation. We find that the effect of scattering on the waveform is roughly given by the Schwarzschild radius of the lens divided by the wavelength of gravitational wave for a compact lens object. If the lenses are smoothly distributed, the effect of scattering is of the order of the convergence field $κ$ along the line of sight to the source. In the short wavelength limit, the amplitude is magnified by $1+κ$, which is consistent with the result in weak gravitational lensing.

astro-ph↗

arXiv2005

Wave propagation in a weak gravitational field and the validity of the thin lens approximation

Wave effects can be important for the gravitational lensing of gravitational waves. In such a case, wave optics must be used in stead of geometric optics. We consider a plane wave entering a lens object and solve numerically the wave equation for three lens models: the uniform density sphere, the singular isothermal sphere, and the Hernquist model. By comparing our numerical solutions with the analytical solutions under the thin lens approximation, we evaluate the error of this approximation. The results show that the relative error of the thin lens approximation is small if the geometrical thickness of the lens is much smaller than the distance between the lens and the observer.

astro-ph↗