Kerr-like black holes shadow surrounded by dark matter halos: Comparison between various dark matter profiles

TL;DR

This paper investigates how dark matter halos influence black hole shadows, finding that dark matter has minimal impact on shadow shape, making it ineffective for distinguishing dark matter profiles.

Contribution

It introduces rotating black hole solutions in various dark matter profiles and compares their shadows to Kerr black holes, highlighting the limited influence of dark matter on shadow characteristics.

Findings

Dark matter halos increase the shadow radius of rotating black holes.

The shape and size of the shadow are largely unaffected by dark matter profile types.

Black hole shadow is not a reliable indicator of dark matter distribution in galactic centers.

Abstract

The study of shadows of static and rotating black holes immersed in various dark matter halo profiles has gained significant attention in recent years. In this paper, we consider the static black hole solution immersed in three dark matter halo profiles (King, Hernquist, and Moore) and, by using the Newman-Janis algorithm, obtain the corresponding rotating black hole solutions. The main goal of the paper is to study the influence of the characteristic density, characteristic radius, and the spin parameter on the inner and outer horizons, the ergoregion, and the shadow radius, and to compare the results with Kerr black holes and other dark matter profiles. Our findings indicate that the shadow radius of rotating black holes immersed in dark matter increases compared to that of the Kerr black hole in the absence of dark matter; however, the impact on the size and shape of the shadow is negligible for King, Hernquist, and Moore profiles, and for all other dark matter halo profiles considered, and is independent of whether the halo is cuspy or cored. Therefore, at least for these Kerr-like black holes, the black hole shadow is not a suitable tool for distinguishing the nature of the dark matter distribution in galactic centers.