Shadow Cast by Black Holes under the Influence of Plasma and Shadow Geometry of Naked Singularities

Abstract

The investigation of black holes and naked singularity shadows has attracted much at tention in modern astrophysics research. The shadow of blackiholes in the presenceiof plasma and naked singularities will be computed in this dissertation. We will observe the propagation of light in a non-magnetizediplasma aroundia Kerr and Ker MOG blackihole. Particularly, we formulate an analytical formula for the boundary curves ofishadow on the observer’s sky, regardless of where they are in the outer communication domain. The shadow’s shape and size that is observed varies based on plasma properties. Recently the Event HorizoniTelescope’s direct imaging of supermassive black holes (SMBHs) at the event horizon scaling factors, allows for testingialternative models to supermassive black holes such as Kerrinaked singularities (KNSs) and Kerr MOG naked singulari ties (KMNSs). Theishadow of KNSs and KMNSs can be utilized to assess the cos micicensorship theory, and KNSs and KMNSs can be used as substitute models for SMBHs by comparing them with black holeishadow measurements.