Dissimilar Donuts in the Sky? Effects of a Pressure Singularity on the Circular Photon Orbits and Shadow of a Cosmological Black Hole

Understand

The black hole observations obtained so far indicate one thing: similar "donuts" exist in the sky.

• But what if some of the observed black hole shadows that will obtained in the future are different from the others? In this work the aim is to show that a difference in the shadow of some observed black holes in the future, might explain the $H_0$-tension problem.
• In this letter we investigate the possible effects of a pressure cosmological singularity on the circular photon orbits and the shadow of galactic supermassive black holes at cosmological redshifts.
• Since the pressure singularity is a global event in the Universe, the effects of the pressure singularity will be imposed on supermassive black holes at a specific redshift.