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arXiv · 2503.04011

Quasi-periodic oscillations of GHz-band polarization in a black hole

Wei Wang·Jiashi Chen·Pengfu Tian·Luis C. Ho·Xiaohui Sun·Pei Wang·Bing Zhang·Zheng Zheng·Xiao Chen·Ping Zhang·Haifan Zhu·Wen Yang·Botao Li
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Abstract

Relativistic jets from accreting black holes (BHs) radiate non-thermal emission which is highly variable in different time scales. Magnetic fields anchored to a rotating BH or accretion disc accelerate and collimate jets of the BH systems. Previous studies on black holes of different mass scales, including supermassive and stellar-mass black holes, only report flux quasi-periodic oscillations in radio, optical, X-ray and gamma-ray bands. No quasi-periodic variations in polarization have yet been detected in any black hole systems. Here, we report the first detection of GHz radio polarization oscillations in GRS 1915+105, which harbors a spinning stellar-mass BH with a relativistic jet. Our observations show that during the increasing phase of radio emission, linear polarization and flux exhibit similar oscillation periods of $\sim 17$ and $33$ seconds, and their variation patterns anti-correlate with each other. These rare, short-period oscillations in both polarization and flux would be important to understand instabilities and special dynamics in magnetized jets.

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Wei Wang, Jiashi Chen, Pengfu Tian, Luis C. Ho, Xiaohui Sun, Pei Wang, Bing Zhang, Zheng Zheng, Xiao Chen, Ping Zhang, Haifan Zhu, Wen Yang, Botao Li. 2025-03-06. Quasi-periodic oscillations of GHz-band polarization in a black hole. https://arxiv.org/abs/2503.04011

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