Transitions and Origin of the Type-B Quasi-Periodic Oscillation in the Black Hole X-ray Binary MAXI~ J1348--630

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 on 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 weak power-law dominated power spectrum, when type-B QPO is present, the corresponding energy spectrum shows an increase in Comptonization component and the need for xillverCp component, and a slight increase of height of the corona when using relxilllp model. Therefore, we suggest that a coupled inner disk-jet region is responsible for the observed type-B QPOs transitions. The time scale for the appearance/disappearance of type-B QPOs is either long or short (seconds), which may indicate an instability of disk-jet structure. For these phenomena, we give the hypothesis that the Bardeen-Petterson effect causes disk-jet structure to align with BH spin axis, or that the disappearance of small-scale jets bound by the magnetic flux tubes lead to the disappearance of type-B QPOs. We observed three events regarding the B/C transitions, one of which occurred in a short time 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 disk changes insignificantly. We suggest that type-C QPOs probably originate from relatively stronger jets or corona.

A variable corona during the transition from type-C to type-B quasi-periodic oscillations in the black hole X-ray binary MAXI J1820+070

“…Both for the type-C and type-B QPOs, the rms amplitude increases with energy up to the highest energy, similar to what is observed in other BHs, e.g., GX 339-4 (Zhang et al 2017), GRS 1915+105 (Zhang et al 2020Karpouzas et al 2021), MAXI J1535+571 (Huang et al 2018;Zhang et al 2022Zhang et al , 2023, and MAXI J1348-630 (Belloni et al 2020;Alabarta et al 2022;Liu et al 2022a). The large rms amplitude at energies above 10 keV (in some cases the rms amplitude of the QPO is ∼12% at 100-200 keV; Ma et al 2021) implies that the variability must be produced by the corona, given that neither the disc nor the reflection component contributessignificantly to the emission at those energies (e.g., Gilfanov 2010;Liu et al 2022a).…”

“…These QPOs have rms amplitudes of ∼4%, 𝑄 ≥6, and are accompanied by a weak low-frequency noise component. One of the explanations for type-B QPOs is that they originate from the jet (e.g., Soleri et al 2008;Stevens & Uttley 2016;de Ruiter et al 2019;Liu et al 2022a). Type-A QPOs are the weakest LFQPOs, they appear in the HSS and are rarely detected (Motta 2016).…”

“…XTE J1859+262 shows a variety of changes in the parameters of the accretion disc during the type-B to type-A QPOs transition (Sriram et al 2013), whereas the transition from type-C to type-A and type-B QPOs in this source appears to be related to relativistic ejection episodes (Casella et al 2004). Liu et al (2022a) reported that the transition between type-B and type-C QPOs in MAXI J1348-630 is associated with an increase of the Comptonized flux, the hardening of the energy spectrum, and a significant change of the inner radius of the accretion disc. Soleri et al (2008) reported the transition between type-C and type-B QPOs in GRS 1915+105 and proposed that the type-B QPOs are related to discrete jet ejections in the SIMS.…”

“…Subsequently, using Monte Carlo simulations Kylafis et al (2020) explained these variations of Γ as the precession of the jet in GX 339-4, further supporting this idea. Liu et al (2022a) studied the type-B QPOs in MAXI J1348-630 and suggested that it also originates from the jet precession; they also attributed the disappearance of the type-B QPOs to instabilities of the disc-jet structure.…”