Distinguishing Black Hole and Naked Singularity in MOG via Inertial Frame Dragging Effect (2007.01347v1)

Abstract: We analyze the generalized spin precession of a test gyroscope around a stationary spacetime i.e. for Kerr-MOG black hole~(BH) in scalar-tensor-vector gravity or modified gravity~(MOG). A detailed study of generalized spin frequency has been done for \emph{non} extremal Kerr-MOG BH, \emph{extremal} Kerr-MOG BH and \emph{naked singularity~(NS)} in comparison to non-extremal BH, extremal BH, and NS of Kerr spacetime. The generalized spin frequency that {we have} computed could be expressed in terms of {the} BH mass parameter, the angular momentum parameter, and the MOG parameter. Moreover, we differentiate the non-extremal BH, extremal BH, and NS via computation of the said precession frequency. The Lense-Thirring~(LT) frequency {can} obtain from generalized spin frequency by taking the limit as $\Omega=0$ i. e. {when the} angular frequency is set to zero limit. Furthermore, we compute the LT frequency for various {values of} angular coordinates i.e. starting from polar to {the} equatorial plane. We show that the LT frequency diverges at the horizon for extremal BH. Finally, we study the accretion disk physics by computing three epicyclic frequencies namely the Keplerian frequency, {the} radial epicyclic frequency and {the} vertical epicyclic frequency. We also compute the periastron frequency and nodal frequency. With the aid of these frequency profiles, {one} can distinguish three compact objects i. e. \emph{non-extremal BH, extremal BH} {and} \emph{NS}.