Superentropic black hole shadows in arbitrary dimensions

Abstract

We investigate the shadow behaviors of the superentropic black holes in arbitrary dimensions. Using the Hamilton–Jacobi mechanism, we first obtain the associated null geodesic equations of motion. By help of a spheric stereographic projection, we discuss the shadows in terms of one-dimensional real curves. Fixing the mass parameter m, we obtain certain shapes being remarkably different than four dimensional geometric configurations. We then study theirs behaviors by varying the black hole mass parameter. We show that the shadows undergo certain geometric transitions depending on the spacetime dimension. In terms of a critical value m_c, we find that the four dimensional shadows exhibit three configurations being the D-shape, the cardioid and the naked singularity associated with m>m_c, m=m_c and m<m_c, respectively. We reveal that the D-shape passes to the naked singularity via a critical curve called cardioid. In higher dimensions, however, we show that such transitional behaviors are removed.