Hotspot image driven by magnetic reconnection in Kerr–anti de Sitter black holes

Abstract Based on the Comisso–Asenjo mechanism, we investigate the kinematic images of plasma before and after magnetic reconnection in Kerr–Anti-de Sitter(Kerr–AdS) black holes. Following a brief review of the Comisso–Asenjo process in Kerr–AdS black holes, we introduce the hotspot model and the imaging method. Building upon these foundational theories, we obtain the trajectory of the plasma and the temporal evolution of the hotspot images. It is found that there are three flares within the observing time, which is driven by the Comisso–Asenjo mechanism. We also discuss the influence of the cosmological parameter on the hotspot imaging. The results indicate that the hotspot image enlarges as the absolute value of $$\Lambda $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>Λ</mml:mi> </mml:math> increases, demonstrating that the cosmological constant significantly affects the hotspot.