Lensing by binary galaxies modelled as isothermal spheres

  title={Lensing by binary galaxies modelled as isothermal spheres},
  author={E. M. Shin and N. Wyn Evans},
  journal={Monthly Notices of the Royal Astronomical Society},
  • E. M. ShinN. Evans
  • Published 23 April 2008
  • Physics
  • Monthly Notices of the Royal Astronomical Society
We consider the problem of lensing by binary galaxies idealized as two isothermal spheres. This is a natural extension of the problem of lensing by binary point masses first studied by Schneider & Weiss. In a wide binary, each galaxy possesses individual tangential, nearly astroidal, caustics and roundish radial caustics. As the separation of the binary is made smaller, the caustics undergo a sequence of metamorphoses. The first metamorphosis occurs when the tangential caustics merge to form a… 

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