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arXiv · 2606.26166

Images of Braneworld black holes with radiatively inefficient accretion flows

Chengjia Chen·Yin Hao·Zelin Zhang·Qiyuan Pan·Jiliang Jing
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Abstract

Horizon-scale imaging acts as a transformative tool for probing spacetime geometry, enabling stringent tests of gravitational theories in the strong-field regime. The Casadio-Fabbri-Mazzacurati(CFM) black hole in braneworld contains an extra parameter that characterizes the tidal effects from the bulk geometry, making it highly valuable for this task. We perform general relativistic radiative transfer (GRRT) simulations and generate synthetic images consistent with Event Horizon Telescope observations of M87*. We find that the tidal parameter imprints nonmonotonic changes on the image morphology, underscoring the intricate coupling between spacetime geometry and the observable radiation from the accreting plasma. We also analyze the image-comparison metric using normalized cross-correlation coefficients and the DSSIM index and find that the magnitudes of these mismatches are on the order of 10^3, which implies that identifying braneworld black holes through black hole images remains challenging even with future ngEHT and BHEX observations.

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Chengjia Chen, Yin Hao, Zelin Zhang, Qiyuan Pan, Jiliang Jing. 2026-06-24. Images of Braneworld black holes with radiatively inefficient accretion flows. https://arxiv.org/abs/2606.26166

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