Probing Hořava-Lifshitz gravity using particle and photon dynamics in the presence of plasma*

Abstract

Abstract We study the particle motion around a black hole (BH) in Hořava-Lifshitz (HL) gravity with the Kehagias-Sfetsos (KS) parameter. First, the innermost stable circular orbit (ISCO) is obtained for massive particles around the BH in HL gravity. We find that the radii of the ISCOs decrease as the KS parameter decreases, meaning that the parameter causes the orbits of particles to move inward with respect to that of the Schwarzschild BH case. Then, the optical properties of a KS BH are studied in detail, that is, the BH shadow and gravitational weak lensing. We demonstrate that the size of the BH shadow decreases under the influence of the KS parameter.