Transitional Dynamics: Unveiling the Coexistence and Interplay of Type B and Type C Quasiperiodic Oscillations in MAXI J1348-630

Abstract Based on broadband timing analysis of Insight-HXMT and Neutron Star Interior Composition Explorer data from the 2019 outburst of the black hole X-ray binary MAXI J1348-630, we report the detection of the coexistence and competitive interplay between Type C and Type B quasiperiodic oscillations (QPOs). Specifically, these two QPO types were detected simultaneously but exhibited distinct energy dependencies: a Type C QPO was dominant in the hard X-ray band (10–30 keV), while a Type B QPO was more prominent in the soft X-ray band (1–10 keV). Further analysis reveals that the emergence of the Type C QPO suppresses the strength of the Type B QPO, particularly above 10 keV. Tracking the detailed evolution of these QPOs, we find that weakening of the Type B QPO coincides with strengthening of the Type C QPO, indicating a competitive interaction between them. These findings reveal a more complex relationship between Type B and Type C QPOs than previously recognized, suggesting they originate from distinct but interacting physical components within the accretion flow and/or jet, and provide new insights into the dynamics of accretion state transitions.