2006/02/28 by M. C. Werner, Marcus C. Werner, N. W. Evans
Physics and Astronomy · #Astrophysical Phenomena and Observations #Astrophysics #Binary black hole #Black Holes and Theoretical Physics #Black hole (networking) #Caustic (mathematics) #Galaxies: Formation, Evolution, Phenomena #Galaxy #Intermediate-mass black hole #Mathematical physics #Physics #Simple (philosophy) #Spin-flip #Stellar black hole #Supermassive black hole #astro-ph
paper · pdf · doi:10.1111/j.1365-2966.2006.10230.x
published as Mon.Not.Roy.Astron.Soc.368:1362-1368,2006 · 7 pages, 4 figures, MNRAS, in press, small changes made
arxiv created 2006/03/21 · openalex publication_date 2006/04/03 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The lensing properties of the Plummer model with a central point mass and external shear are derived, including the image multiplicities, critical curves and caustics. This provides a simple model for a flattened galaxy with a central supermassive black hole. For the Plummer model with black hole, the maximum number of images is four, provided the black hole mass is less than an upper bound which is calculated analytically. This introduces a method to constrain black hole masses by counting images, thus applicable at cosmological distance. With shear, the maximum number of images is six and we illustrate the occurrence of an astroid caustic and two metamorphoses.