Energetic processes around the rotating black hole surrounded by dark matter halo

The energy extraction from the rotating black hole (BH) surrounded by the Dehnen-type dark matter (DM) halo is explored. Firstly, we obtain an axially symmetric BH spacetime metric using the Newman-Janis algorithm and then analyze the spacetime singularity by defining the Kretschmann scalar. Moreover, we numerically verify that the null, weak, dominant and strong energy conditions are satisfied within the parameter domain explored in this work. We then turn to investigate the effect of spacetime parameters on the behavior of the event horizon and ergosphere of the BH. The results indicate that the values of both event horizon and ergosphere radii increase under the influence of the DM halo parameters. Also, the timelike geodesics are studied by using the Lagrangian formalism. In particular, we analyze the impact of DM halo parameters on the constants of motion for massive neutral particles. It was found that the axial component of the specific angular momentum slightly increases with the rise of the DM halo parameters and vice versa for specific energy. In addition, we study the energy extraction processes, which are the Penrose process and the Blandford-Znajek mechanism. Our results show that the values of the energy efficiency of the Penrose process and the jet power of the Blandford-Znajek mechanism decrease with the rise of the density and radius of the DM halo, while the BH’s spin plays a key role in the energy extraction.

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