2000/02/22 by Charles R. Keeton, C. R. Keeton, Shude Mao +3
Engineering · Physics and Astronomy · #Astronomy and Astrophysical Research #Caustic (mathematics) #Einstein ring #Galaxies: Formation, Evolution, Phenomena #Galaxy #Gravitation #Gravitational lens #Lens (geology) #Magnification #Space Technology and Applications #Strong gravitational lensing #Wavelength #astro-ph
paper · pdf · doi:10.1086/309087
30 pages, including 12 postscript figures; accepted for publication in ApJ
arxiv created 2000/02/22 · openalex publication_date 2000/07/10 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We study the problem of gravitational lensing by an isothermal elliptical density galaxy in the presence of a tidal perturbation. When the perturbation is fairly strong and oriented near the galaxy's minor axis, the lens can produce image configurations with six or even eight highly magnified images lying approximately on a circle. We classify the caustic structures in the model and identify the range of models that can produce such lenses. Sextuple and octuple lenses are likely to be rare because they require special lens configurations, but a full calculation of the likelihood will have to include both the existence of lenses with multiple-lens galaxies and the strong magnification bias that affects sextuple and octuple lenses. At optical wavelengths, these lenses would probably appear as partial or complete Einstein rings, but at radio wavelengths, the individual images could probably be resolved.