https://doi.org/10.1140/epjc/s10052-025-15257-9
Regular Article - Theoretical Physics
Hotspot images driven by magnetic reconnection in Kerr–Sen black hole
1
School of Material Science and Engineering, Chongqing Jiaotong University, 400074, Chongqing, China
2
College of Physics and Electronic Engineering, Chongqing Normal University, 401331, Chongqing, China
a
This email address is being protected from spambots. You need JavaScript enabled to view it.
Received:
29
November
2025
Accepted:
22
December
2025
Published online:
19
January
2026
Abstract
In the Kerr–Sen black hole, this study investigates the changes in hotspot images before and after the occurrence of magnetic reconnection. After reviewing the Comisso–Asenjo magnetic reconnection process and introducing the hotspot imaging method, we examine the temporal evolution of hotspot intensity, including when energy extraction occurs, when it does not occur, and when the observer’s azimuthal angle is altered. We also discuss the influence of the black hole’s expansion parameter and spin on hotspot imaging. The results indicate that the first flare may serve as a potential signature of ongoing energy extraction; changing the observer’s azimuthal angle may alter the time interval between the first and second flares; a larger expansion parameter makes it more difficult to identify the energy extraction signal, and a higher spin also makes it more challenging to detect the energy extraction signal.
© The Author(s) 2026
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.
