Strong deflection gravitational lensing by a Lee-Wick ultracompact object

We study strong deflection gravitational lensing by a Lee-Wick ultracompact object. Its unique feature is a series of relativistic images inside its photon sphere, which are absent in the case of a black hole. We obtain its observables and estimate them for the supermassive black holes Sgr A* and M87* respectively in the Galactic center and in the center of M87. We find that the innermost relativistic image is a very promising signature according to its angular separation from the photon sphere and its considerable brightness. A preliminary bound on the UV scale of such an object is estimated based on the shadow of M87*.