Polarized image of a rotating black hole surrounded by a cold dark matter halo

Xin Qin; Songbai Chen; Zelin Zhang; Jiliang Jing

doi:10.1140/epjc/s10052-023-11300-9

2023 Impact factor 4.2

Particles and Fields

Open Access

Eur. Phys. J. C (2023) 83: 159
https://doi.org/10.1140/epjc/s10052-023-11300-9

Regular Article - Theoretical Physics

Polarized image of a rotating black hole surrounded by a cold dark matter halo

Xin Qin¹, Songbai Chen¹^,2^b, Zelin Zhang¹ and Jiliang Jing¹^,2

¹ Department of Physics, Institute of Interdisciplinary Studies, Synergetic Innovation Center for Quantum Effects and Applications, Hunan Normal University, 410081, Changsha, Hunan, People’s Republic of China
² Center for Gravitation and Cosmology, College of Physical Science and Technology, Yangzhou University, 225009, Yangzhou, People’s Republic of China

^b csb3752@hunnu.edu.cn

Received: 6 January 2023
Accepted: 3 February 2023
Published online: 18 February 2023

Abstract

We have studied the polarized image of an equatorial emitting ring around a rotating black hole surrounded by a cold dark matter (CDM) halo. Results show that the CDM halo density has the similar effects of the halo’s characteristic radius on the polarized image for the black hole. The effects of the CDM halo on the polarized image depend on the magnetic field configuration, the fluid velocity and the observed inclination. With the increase of the CDM halo parameters, the observed polarization intensity decreases when the magnetic field lies in equatorial plane, but in the case where the magnetic field is perpendicular to the equatorial plane, the change of the observed polarization intensity with CDM halo also depends on the position of the emitting point in the ring. The change of the electric vector position angle (EVPA) with the CDM halo becomes more complicated. Our results also show that the influence of the CDM halo on the polarized image is generally small, which are consistent with the effects of dark matter halo on black hole shadows. These results could help to further understand dark matter from black hole images.

© The Author(s) 2023

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