Regular Article - Theoretical Physics
Strong deflection gravitational lensing by an Einstein–Lovelock ultracompact object
School of Astronomy and Space Science, Nanjing University, 210023, Nanjing, China
2 Purple Mountain Observatory, Chinese Academy of Sciences, 210023, Nanjing, China
Accepted: 13 February 2022
Published online: 22 February 2022
We investigate the strong deflection gravitational lensing by an Einstein–Lovelock ultracompact object. Its unique features are the relativistic images inside its photon sphere which are absent for an Einstein–Lovelock black hole. We obtain its lensing observables and evaluate their observability for the direct images of two supermassive black holes in the Galaxy and M87 respectively, Sgr A* and M87*, and for the relativistic microlensing on a star closely around Sgr A*. We find that although it is impossible to tell difference of the ultracompact object from the black hole in Einstein–Lovelock gravity by the direct images, it might be possible to distinguish the Einstein–Lovelock ultracompact object by measuring the total flux of the relativistic microlensing in the not-so-far future.
© The Author(s) 2022
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