Instability of a Kerr-type naked singularity due to light and matter accretion and its shadow

Understand

We study null and timelike constant radii geodesics in the environment of an over-spinning putative Kerr-type naked singularity.

• We are particularly interested in two topics: first, the differences of the shadows of the naked rotating singularity and the Kerr black hole; and second, the spinning down effect of the particles falling from the accretion disk.
• Around the naked singularity, the non-equatorial prograde orbits in the Kerr black hole remain intact up to a critical rotation parameter ($\alpha=\sqrt{6 \sqrt{3}-9}$) and cease to exist above this value [Eur.
• Phys.