Trajectories of photons in modified Hayward black hole spacetime

Abstract

We study the trajectories of photons in modified Hayward black hole spacetime. Three kinds of horizons are distinguished by analyzing the lapse function of modified Hayward black hole spacetime. Through plotting the effective potential with different values of parameters, it is found that the parameter [Formula: see text] has more conspicuous effects than parameters [Formula: see text] ([Formula: see text] is associated with the time-delay) and [Formula: see text] ([Formula: see text] is related to the 1-loop quantum corrections) for the effective potential. The change of the parameters ([Formula: see text], [Formula: see text] and [Formula: see text]) has an obvious influence on unstable circular orbits. The structure of null geodesic is simpler than that of time-like geodesic. The stable circular orbits and the bound orbits are not included for the photon trajectories. By analyzing the corresponding effective potential, all possible orbits of null geodesic are found. The radius of unstable circular orbit equals 2.8790 for fixed [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text].