Transitions and Origin of the Type-B Quasi-periodic Oscillations in the Black Hole X-Ray Binary MAXI J1348–630
He-Xin Liu, Y. Huang, Qingcui Bu, Wei Yu, Zi-Xu Yang, L. Zhang, Ling-Da Kong, G. Xiao, Jin‐Lu Qu, Shuang‐Nan Zhang, S. Zhang, L. M. Song, S. M. Jia, Xiang Ma, Lian Tao, M. Y. Ge, Q. Z. Liu, Jing‐Zhi Yan, Rivera O.C, Xiaoqin Ren, D. K. Zhou, T. M. Li, Bowen Wu, Y. C. Xu, Y. F. Du, Yunchong Fu, Yihong Xiao, Guoqiang Ding, Xiaoxia Yu
Abstract
Abstract The fast transitions between different types of quasi-periodic oscillations (QPOs) are generally observed in black hole transient sources (BHTs). We present a detailed study of the timing and spectral properties of the transitions of type-B QPOs in MAXI J1348–630, observed by Insight-HXMT. The fractional rms variability–energy relationship and energy spectra reveal that type-B QPOs probably originate from jet precession. Compared to a weak power-law dominated power spectrum, when type-B QPOs are present, the corresponding energy spectrum shows an increase in the Comptonization component and the need for the xillverCp component, and a slight increase in the height of the corona when using the relxilllp model. Therefore, we suggest that a coupled inner disk-jet region is responsible for the observed type-B QPO transitions. The timescale for the appearance/disappearance of type-B QPOs is either long or short (seconds), which may indicate instability of the disk-jet structure. For these phenomena, we hypothesize that the Bardeen–Petterson effect causes the disk-jet structure to align with the BH spin axis or that the disappearance of small-scale jets bound by the magnetic flux tubes leads to the disappearance of type-B QPOs. We observed three events regarding the B/C transitions, one of which occurred over a short time period from ∼9.2 Hz (C) to ∼4.8 Hz (B). The energy spectral analysis for the other two transitions shows that when type-C QPO is present, the Comptonization flux is higher, the spectrum is harder, and the inner radius of the disk changes insignificantly. We suggest that type-C QPOs probably originate from relatively stronger jets or the corona.