The combined influence of spin and charge on dark matter spikes in a Kerr-Newman black hole

Abstract

Dark matter is an invisible form of matter that does not interact with light, its detection is primarily through gravity, and its presence is fundamental to understanding galactic dynamics. This study investigates the distribution of collision-less dark matter around an adiabatically growing Kerr-Newman black hole using a fully general relativistic framework. While the previous literature has addressed static and rotating black holes, the combined influence of spin and electric charge has not been explored sufficiently. Using a phase-space analysis grounded in the Kerr-Newman metric, we demonstrate that a moderate charge parameter (Q = 0.3) dramatically enhances the dark matter spike, yielding peak densities approximately three times greater than those in the neutral Kerr case. Furthermore, the results confirm that black hole rotation induces frame-dragging effects, creating a distinct anisotropy along the equatorial plane.