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arXiv · 2511.04264

Revealing an Oscillating and Contracting Compact Corona near the Event Horizon of the Supermassive Black Hole in 1ES 1927+654

Qing-Cang Shui·Shu Zhang·Shuang-Nan Zhang·Hua Feng·Yu-Peng Chen·Long Ji·Ling-Da Kong·Liang Zhang·Jing-Qiang Peng·Peng-Ju Wang
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Abstract

Dynamic processes in the accretion flow near black holes produce X-ray flux variability, sometimes quasi-periodic. Determining its physical origin is key to mapping accretion geometry but remains unresolved. We perform a novel phase-resolved analysis on a newly discovered quasi-periodic oscillation (QPO) in the active galactic nucleus 1ES 1927+654. For the first time in a supermassive black hole (SMBH), we detect a unique `U'-shaped QPO lag-energy spectrum and observe coronal spectral variability over the QPO phase. We find that the QPO is adequately explained by plasma resonant oscillations within a corona. Modeling of QPO spectral properties and reverberation mapping reveal that the corona is contracting and confined to only a few gravitational radii regions near the SMBH, consistent with theoretical predictions for a decreasing QPO period of near 10 minutes. These results present the first observational evidence for an oscillating and contracting compact corona around an SMBH.

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Qing-Cang Shui, Shu Zhang, Shuang-Nan Zhang, Hua Feng, Yu-Peng Chen, Long Ji, Ling-Da Kong, Liang Zhang, Jing-Qiang Peng, Peng-Ju Wang. 2025-11-06. Revealing an Oscillating and Contracting Compact Corona near the Event Horizon of the Supermassive Black Hole in 1ES 1927+654. https://arxiv.org/abs/2511.04264

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