Polarized quasiperiodic oscillations reveal kink instability in magnetized jets of black holes

The dynamics and instability of the magnetized jets connected to jet acceleration are complicated and are not yet well understood. Quasi-periodic oscillations (QPOs) as special timing features in black hole systems can directly probe dynamics and structure of accreting and outflow materials. Recently, GHz-band radio polarization oscillations in a stellar-mass black hole are reported, and the physical origin is unclear. We propose that the QPOs in both radio flux and linear polarization will be connected to kink instability in relativistic magnetized jets. The simulations are performed to fit the observed curves of radio flux and linear polarization modulations, in addition, the kink instability model well explains the anti-correlation between flux and linear polarization. These polarized QPOs provide evidence for kink stability in relativistic jets, a phenomenon of significant theoretical importance for understanding the magnetic field configuration near the black hole, as well as for particle acceleration in jets.