2025/09/01 by Cai, Ziqiang, Ban, Zhenglong, Liang, Qi-Qi +2
#FOS: Physical sciences #General Relativity and Quantum Cosmology (gr-qc)
paper · doi:10.48550/arxiv.2509.01226
In this paper, we generate a rotating charged black hole (BH) with scalar hair via the Newman--Janis algorithm (NJA) and study its thin accretion disk and shadow. The structure of the event horizon and ergosurface is analyzed in detail, revealing how the charge parameter Q and scalar hair parameter s influence the spacetime geometry. We analyze the energy flux and temperature distribution of the accretion disk, finding that increasing either Q or s leads to higher energy flux and peak temperature. The BH shadow is also examined, showing that its apparent size decreases monotonically with increasing Q or s. Notably, in the near-extremal regime, the shadow develops a distinctive cuspy edge, indicative of strong light bending in the scalarized and charged spacetime. By comparing the theoretically predicted shadow diameter with Event Horizon Telescope (EHT) observations of Sgr A^*, we derive observational constraints on the model parameters. For inclination angles of 17^∘ and 90^∘, a joint analysis constrains the charge parameter to 0