A&A 438, L5-L8 (2005)

DOI: 10.1051/0004-6361:200500140

*Letter*

## Scattering of gravitational waves by the weak gravitational fields of lens objects

**R. Takahashi**

^{1}, T. Suyama^{2}and S. Michikoshi^{2}^{1}Division of Theoretical Astronomy, National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588, Japan

^{2}Department of Physics, Kyoto University, Kyoto 606-8502, Japan

(Received 17 March 2005 / Accepted 7 June 2005 )

** Abstract **

We consider the scattering of 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 along the line of sight to the source. In the short wavelength limit, the amplitude is magnified by , which is consistent with the result in weak gravitational lensing.

**Key words:**gravitational lensing

**--**gravitational waves

**--**scattering

**©**

*ESO 2005*