https://doi.org/10.1140/epjc/s10052-025-14441-1
Regular Article - Theoretical Physics
Optical images of the Kerr–Sen black hole and thin accretion disk
1
College of Physics and Electronic Engineering, Chongqing Normal University, 401331, Chongqing, People’s Republic of China
2
Center for Gravitational Wave Experiment, National Microgravity Laboratory, Institute of Mechanics, Chinese Academy of Sciences, 100190, Beijing, People’s Republic of China
3
Guangxi Key Laboratory for Relativistic Astrophysics, School of Physical Science and Technology, Guangxi University, 530004, Nanning, People’s Republic of China
4
School of Physics and Astronomy, China West Normal University, 637009, Nanchong, People’s Republic of China
a
sguophys@126.com
b
lilifang@imech.ac.cn
Received:
7
April
2025
Accepted:
15
June
2025
Published online:
7
July
2025
This paper investigates the observable properties of a Kerr–Sen black hole surrounded by a thin accretion disk, focusing on the impact of the black hole’s spin and charge on the image. Using ray-tracing techniques, we conduct a detailed analysis of the black hole’s image, redshift distribution, and intensity distributions at different observation frequencies. The results demonstrate that spin has a more significant effect on the distortion of the inner shadow than charge, and the observer’s inclination angle plays a critical role in shaping the redshift distribution, especially near the innermost stable circular orbit. Additionally, the intensity is found to be higher at 86 GHz than at 230 GHz. This study highlights the crucial role of the accretion disk’s geometry in determining the black hole’s image and redshift effects, thereby providing a refined theoretical framework to guide future observational efforts targeting the Kerr–Sen black hole and its electromagnetic signals.
© 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.
