Gravitational Waves from Braneworld Black Holes

Abstract

In this article, we present the black string model of a braneworld black hole and analyze its perturbations. We develop the perturbation formalism for Randall–Sundrum model from first principles and discuss the weak-field limit of the model in the solar system. We derive explicit equations of motion for the axial and spherical gravitational waves in the black string background. These are solved numerically in various scenarios, and the characteristic late-time signal from a black string is obtained. We find that if one waits long enough after some transient event, the signal from the string will be a superposition of nearly monochromatic waves with frequencies corresponding to the masses of the Kaluza–Klein modes of the model. We estimate the amplitude of the spherical component of these modes when they are excited by a point particle orbiting the string.