2004/02/29 by Ryuichi Takahashi · 2 citations
Physics and Astronomy · #Astrophysics #Beam (structure) #Black Holes and Theoretical Physics #Cosmology and Gravitation Theories #Diffraction #Einstein radius #Galaxy #Gaussian optics #Geometrical optics #Gravitational lens #Gravitational wave #Lens (geology) #Optics #Paraxial approximation #Physics #Pulsars and Gravitational Waves Research #Weak gravitational lensing #astro-ph
paper · pdf · doi:10.1051/0004-6361:20040212
published as Astron.Astrophys. 423 (2004) 787-792 · 9 pages, 4 figures. Revised version accepted for publication in A&A
arxiv created 2004/05/10 · openalex publication_date 2004/08/12 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The gravitational lensing of gravitational waves should be treated in wave optics instead of geometrical optics when the wave length λ of the gravitational waves is larger than the Schwarzschild radius of the lens mass M. Wave optics is based on the diffraction integral which represents the amplification of the wave amplitude by lensing. We study the asymptotic expansion of the diffraction integral in the powers of the wave length λ. The first term, arising from the short wavelength limit , corresponds to the geometrical optics limit. The second term, being of the order of , is the leading correction term arising from the diffraction effect. Analysing this correction term, we find that (1) the lensing magnification μ is modified to , where δ is of the order of , and (2) if the lens has a cuspy (or singular) density profile at center (), the diffracted image is formed at the lens center with magnification .