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Gravitational lensing by extremal rotating black holes in the strong deflection limit

Fabiano Feleppa1,2,3,*, Valerio Bozza1,2,†, and Welmoed Marit de Graaf1,‡

  • *Contact author: ffeleppa@unisa.it
  • Contact author: vbozza@unisa.it
  • Contact author: w.degraaf@studenti.unisa.it

Phys. Rev. D 114, 044053 – Published 17 August, 2026

DOI: https://doi.org/10.1103/4lhw-mxnh

Abstract

In the strong deflection regime, light rays passing close to an astrophysical black hole may remain trapped near unstable photon orbits for a long time before escaping to infinity. The traditional strong-deflection limit, which accurately describes the logarithmic divergence of the deflection angle for spherically symmetric and slowly rotating black holes, breaks down when the relevant prograde critical photon orbit coincides with the degenerate horizon of an extremal rotating black hole. We present a new strong deflection limit expansion for this horizon critical orbit, covering a general class of extremal rotating black holes. We show that the deflection angle exhibits a stronger power-law divergence in addition to the logarithmic divergence. For an adequate description of higher-order images, additional terms in the expansion must be retained. We first study prograde gravitational lensing in the equatorial plane and then extend the analysis to quasiequatorial motion, which allows us to calculate the magnification of the higher-order images and the position of the caustic points. We finally apply the general framework to explicit examples, including the Kerr, Kerr-Newman, and Kerr-Sen metrics.

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References (84)

  1. K. Akiyama, A. Alberdi, W. Alef, K. Asada, R. Azulay, A.-K. Baczko, D. Ball et al. (Event Horizon Telescope Collaboration), Astrophys. J. Lett. 875, L1 (2019).
  2. K. Akiyama, A. Alberdi, W. Alef, K. Asada, R. Azulay, A.-K. Baczko, D. Ball et al. (Event Horizon Telescope Collaboration), Astrophys. J. Lett. 875, L2 (2019).
  3. K. Akiyama, A. Alberdi, W. Alef, K. Asada, R. Azulay, A.-K. Baczko, D. Ball et al. (Event Horizon Telescope Collaboration), Astrophys. J. Lett. 875, L3 (2019).
  4. K. Akiyama, A. Alberdi, W. Alef, K. Asada, R. Azulay, A.-K. Baczko, D. Ball et al. (Event Horizon Telescope Collaboration), Astrophys. J. Lett. 875, L4 (2019).
  5. K. Akiyama, A. Alberdi, W. Alef, K. Asada, R. Azulay, A.-K. Baczko, D. Ball et al. (Event Horizon Telescope Collaboration), Astrophys. J. Lett. 875, L5 (2019).
  6. K. Akiyama, A. Alberdi, W. Alef, K. Asada, R. Azulay, A.-K. Baczko, D. Ball et al. (Event Horizon Telescope Collaboration), Astrophys. J. Lett. 875, L6 (2019).
  7. P. Kocherlakota, L. Rezzolla, H. Falcke, C. M. Fromm, M. Kramer, Y. Mizuno, A. Nathanail et al. (Event Horizon Telescope Collaboration), Phys. Rev. D 103, 104047 (2021).
  8. K. Akiyama, A. Alberdi, W. Alef, J. C. Algaba, R. Anantua, K. Asada, R. Azulay, U. Bach, A.-K. Baczko, D. Ball et al. (Event Horizon Telescope Collaboration), Astrophys. J. Lett. 930, L12 (2022).
  9. K. Akiyama, A. Alberdi, W. Alef, J. C. Algaba, R. Anantua, K. Asada, R. Azulay, U. Bach, A.-K. Baczko, D. Ball et al. (Event Horizon Telescope Collaboration), Astrophys. J. Lett. 930, L13 (2022).
  10. K. Akiyama, A. Alberdi, W. Alef, J. C. Algaba, R. Anantua, K. Asada, R. Azulay, U. Bach, A.-K. Baczko, D. Ball et al. (Event Horizon Telescope Collaboration), Astrophys. J. Lett. 930, L14 (2022).
  11. K. Akiyama, A. Alberdi, W. Alef, J. C. Algaba, R. Anantua, K. Asada, R. Azulay, U. Bach, A.-K. Baczko, D. Ball et al. (Event Horizon Telescope Collaboration), Astrophys. J. Lett. 930, L15 (2022).
  12. K. Akiyama, A. Alberdi, W. Alef, J. C. Algaba, R. Anantua, K. Asada, R. Azulay, U. Bach, A.-K. Baczko, D. Ball et al. (Event Horizon Telescope Collaboration), Astrophys. J. Lett. 930, L16 (2022).
  13. K. Akiyama, A. Alberdi, W. Alef, J. C. Algaba, R. Anantua, K. Asada, R. Azulay, U. Bach, A.-K. Baczko, D. Ball et al. (Event Horizon Telescope Collaboration), Astrophys. J. Lett. 930, L17 (2022).
  14. C. Darwin, Proc. R. Soc. A 249, 180 (1959).
  15. R. d’. E. Atkinson, Astron. J. 70, 517 (1965).
  16. C. W. Misner, K. S. Thorne, and J. A. Wheeler, Gravitation (W. H. Freeman, San Francisco, 1973).
  17. J.-P. Luminet, Astron. Astrophys. 75, 228 (1979).
  18. H. C. Ohanian, Am. J. Phys. 55, 428 (1987).
  19. K. S. Virbhadra and G. F. R. Ellis, Phys. Rev. D 62, 084003 (2000).
  20. S. Frittelli, T. P. Kling, and E. T. Newman, Phys. Rev. D 61, 064021 (2000).
  21. V. Perlick, Phys. Rev. D 69, 064017 (2004).
  22. V. Bozza, S. Capozziello, G. Iovane, and G. Scarpetta, Gen. Relativ. Gravit. 33, 1535 (2001).
  23. V. Bozza, Phys. Rev. D 66, 103001 (2002).
  24. V. Bozza, Phys. Rev. D 67, 103006 (2003).
  25. V. Bozza, F. De Luca, G. Scarpetta, and M. Sereno, Phys. Rev. D 72, 083003 (2005).
  26. F. Feleppa, O. Yu. Tsupko, and V. Bozza, Phys. Rev. D 110, 064031 (2024).
  27. F. Feleppa, O. Yu. Tsupko, and V. Bozza, Phys. Rev. D 111, 044018 (2025).
  28. C.-M. Claudel, K. S. Virbhadra, and G. F. R. Ellis, J. Math. Phys. (N.Y.) 42, 818 (2001).
  29. W. Hasse and V. Perlick, Gen. Relativ. Gravit. 34, 415 (2002).
  30. V. Perlick, Living Rev. Relativity 7, 9 (2004).
  31. S. V. Iyer and A. O. Petters, Gen. Relativ. Gravit. 39, 1563 (2007).
  32. K. S. Virbhadra and C. R. Keeton, Phys. Rev. D 77, 124014 (2008).
  33. G. S. Bisnovatyi-Kogan and O. Yu. Tsupko, Astrophysics 51, 99 (2008).
  34. N. Mukherjee and A. S. Majumdar, Gravitation Cosmol. 15, 263 (2009).
  35. A. Tarasenko, Phys. Rev. D 81, 123005 (2010).
  36. E. F. Eiroa and C. M. Sendra, Classical Quantum Gravity 28, 085008 (2011).
  37. S.-W. Wei, Yu.-X. Liu, C.-E. Fu, and K. Yang, J. Cosmol. Astropart. Phys. 10 (2012) 053.
  38. G. Li, Y. Zhang, L. Zhang, Z. Feng, and X. Zu, Int. J. Theor. Phys. 54, 1245 (2015).
  39. A. Alhamzawi and R. Alhamzawi, Gen. Relativ. Gravit. 48, 167 (2016).
  40. N. Tsukamoto, Phys. Rev. D 94, 124001 (2016).
  41. G. F. Aldi and V. Bozza, J. Cosmol. Astropart. Phys. 02 (2017) 033.
  42. D.-C. Dai, D. Stojkovic, and G. D. Starkman, Phys. Rev. D 98, 124027 (2018).
  43. F. Aratore and V. Bozza, J. Cosmol. Astropart. Phys. 10 (2021) 054.
  44. X.-M. Kuang, Z.-Y. Tang, B. Wang, and A. Wang, Phys. Rev. D 106, 064012 (2022).
  45. G. Abbas, A. Övgün, A. Mahmood, and M. Zubair, Universe 9, 130 (2023).
  46. Y. Duan, S. Lin, and J. Jia, J. Cosmol. Astropart. Phys. 07 (2023) 036.
  47. F. Aratore and V. Bozza, J. Cosmol. Astropart. Phys. 07 (2024) 033.
  48. A. Vachher and S. G. Ghosh, J. High Energy Astrophys. 45, 75 (2025).
  49. F. Feleppa, F. Aratore, and V. Bozza, Phys. Rev. D 112, 044007 (2025).
  50. N. Tsukamoto, Phys. Rev. D 113, 104016 (2026).
  51. T. Igata, Phys. Rev. D 113, 044042 (2026).
  52. T. Igata, Phys. Rev. D 113, 024036 (2026).
  53. T. Igata, T. Sasaki, and N. Tsukamoto, Phys. Rev. D 113, 104022 (2026).
  54. S. E. Gralla, D. E. Holz, and R. M. Wald, Phys. Rev. D 100, 024018 (2019).
  55. M. D. Johnson, A. Lupsasca, A. Strominger, G. N. Wong, S. Hadar, D. Kapec, R. Narayan, A. Chael, C. F. Gammie, P. Galison et al., Sci. Adv. 6, eaaz1310 (2020).
  56. S. E. Gralla and A. Lupsasca, Phys. Rev. D 102, 124003 (2020).
  57. S. E. Gralla, A. Lupsasca, and D. P. Marrone, Phys. Rev. D 102, 124004 (2020).
  58. S. E. Gralla and A. Lupsasca, Phys. Rev. D 101, 044031 (2020).
  59. M. Wielgus, Phys. Rev. D 104, 124058 (2021).
  60. A. E. Broderick, P. Tiede, D. W. Pesce, and R. Gold, Astrophys. J. 927, 6 (2022).
  61. D. Ayzenberg, Classical Quantum Gravity 39, 105009 (2022).
  62. M. Guerrero, G. J. Olmo, D. Rubiera-Garcia, and D. S.-C. Gómez, Phys. Rev. D 106, 044070 (2022).
  63. G. S. Bisnovatyi-Kogan and O. Yu. Tsupko, Phys. Rev. D 105, 064040 (2022).
  64. O. Yu. Tsupko, Phys. Rev. D 106, 064033 (2022).
  65. A. Eichhorn, A. Held, and P.-V. Johannsen, J. Cosmol. Astropart. Phys. 01 (2023) 043.
  66. A. E. Broderick, K. Salehi, and B. Georgiev, Astrophys. J. 958, 114 (2023).
  67. P. Kocherlakota, L. Rezzolla, R. Roy, and M. Wielgus, Phys. Rev. D 109, 064064 (2024).
  68. P. Kocherlakota, L. Rezzolla, R. Roy, and M. Wielgus, Mon. Not. R. Astron. Soc. 531, 3606 (2024).
  69. F. Aratore, O. Yu. Tsupko, and V. Perlick, Phys. Rev. D 109, 124057 (2024).
  70. O. Yu. Tsupko, F. Aratore, and V. Perlick, Phys. Rev. D 113, 024017 (2026).
  71. S. E. Gralla, A. Lupsasca, and A. Strominger, Mon. Not. R. Astron. Soc. 475, 3829 (2018).
  72. B.-R. Chen, T. Hsieh, and D.-S. Lee, Phys. Rev. D 111, 024058 (2025).
  73. F. Tamburini, B. Thidé, and M. Della Valle, Mon. Not. R. Astron. Soc. 492, L22 (2020).
  74. F. Tamburini, F. Feleppa, and B. Thidé, Int. J. Mod. Phys. D 30, 2142017 (2021).
  75. F. Tamburini, F. Feleppa, I. Licata, and B. Thidé, Phys. Rev. A 104, 013718 (2021).
  76. G. N. Gyulchev and S. S. Yazadjiev, Phys. Rev. D 75, 023006 (2007).
  77. V. Bozza and G. Scarpetta, Phys. Rev. D 76, 083008 (2007).
  78. E. T. Newman and A. Janis, J. Math. Phys. (N.Y.) 6, 915 (1965).
  79. E. T. Newman and A. Janis, J. Math. Phys. (N.Y.) 6, 902 (1965).
  80. E. T. Newman, E. Couch, K. Chinnapared, A. Exton, A. Prakash, and R. Torrence, J. Math. Phys. (N.Y.) 6, 918 (1965).
  81. S. Ulbricht and R. Meinel, Classical Quantum Gravity 32, 147001 (2015).
  82. A. Sen, Phys. Rev. Lett. 69, 1006 (1992).
  83. S. Chandrasekhar, The Mathematical Theory of Black Holes, International Series of Monographs on Physics Vol. 69 (Oxford University Press, Oxford, 1983).
  84. V. Bozza, Phys. Rev. D 78, 063014 (2008).

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