Study on Quasi-Periodic Oscillations of Black Hole X-Ray Binary Swift J1727.8–1613 with the Insight-Hxmt Observations During 2023 Outburst

The X-ray timing properties serve as crucial tool to understand the physical mechanism, such as accretion and jet physics, of black hole X-ray binary (BH XRBs). The study carried out a systematic timing analysis of the Swift J1727.8-1613. The observational data come from the Hard X-ray Modulation Telescope (Insight-HXMT) in 2023, when Swift J1727.8-1613 was transitioning from low-hard state (LHS) to the hard-intermediate state (HIMS). We analyzed their power density spectrum （PDS） and find an obvious type-C quasi-periodic oscillations (QPOs) with the QPO frequency increasing from 0.2 Hz to 1.8 Hz. Detailed light curve and power spectral analysis revealed that the root-mean-square (RMS) amplitude of the QPOs gradually decreased from ∼14% to ∼10%. These observational characteristics show excellent agreement with predictions from the Lense-Thirring precession model under the truncated disk scenario, suggesting that the increasing precession frequency results from the inward migration of the inner accretion disk radius.