https://doi.org/10.1140/epjc/s10052-025-14346-z
Regular Article - Theoretical Physics
Effects of hair on the image of a rotating black hole illuminated by a thin accretion disk
1
Center for Gravitation and Cosmology, Yangzhou University, 225009, Yangzhou, China
2
Department of Astronomy, School of Physics and Technology, Wuhan University, 430072, Wuhan, China
3
Research center for theoretical physics, School of Science, Jiangsu University of Science and Technology, 212100, Zhenjiang, China
Received:
28
December
2024
Accepted:
22
May
2025
Published online:
7
June
2025
In this paper, we investigate the shadow and optical appearance of the hairy Kerr black hole illuminated by a thin accretion disk. The deformation parameter and hair parameter
are found to influence the motions of accretion as well as the redshift effect of the photon, such that they significantly affect the shadow and image of the hairy Kerr black hole. In particular,
suppresses the shadow size of the black hole while
enhances it. We then analyze the widths of the direct, lensed ring and photon ring emission regions for the thin accretion disk. It is found that the widths of the direct emission and lensed ring emission change slightly with the parameters, whereas the width of the photon ring emission increases dramatically as
decreases. This feature provides more favorable conditions for observing the photon rings of black hole. Finally, we study the redshift of the direct and lensed images, showing that the maximal blueshift point is shifted by the change of the parameters. We argue that our study provides a preliminary theoretical prediction that the image of the hairy Kerr black hole, especially the photon ring structure, may be used to constrain the hair parameters with future high-precision astronomical observation.
© The Author(s) 2025
Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
Funded by SCOAP3.