Multi-level images around Kerr-Newman black holes

  title={Multi-level images around Kerr-Newman black holes},
  author={Yehui Hou and P. Liu and Minyong Guo and Haopeng Yan and Bin Chen},
  journal={Classical and Quantum Gravity},
We study the lensing effects of Kerr-Newman (KN) black holes and the multi-level images of luminous sources around the black holes. We obtain the analytic forms of the lens equations in KN spacetime and derive approximately their limiting forms for photon emissions near the bounded photon orbits. After deriving the expressions of three key parameters γ, δ and τ, we investigate the primary, the secondary and the higher-order images of spherical sources and equatorial disk-like sources. In… 
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