QPO signatures of disk restoration after type-I X-ray bursts from 4U~1636$-$536
QPO signatures of disk restoration after type-I X-ray bursts from 4U~1636$-$536
Type-I thermonuclear bursts (TNBs) from neutron star low-mass X-ray binaries (NSLMXBs) originate on the neutron star's surface from the unstable burning of the accreted material. On the other hand, kHz quasi-periodic oscillations (QPOs) are thought to originate in the innermost regions of the in-spiraling accretion disk. Due to the violent nature of the bursts, it is anticipated that Type-I TNBs will impact the inner accretion flow, and, therefore, the kHz QPOs. In this work, we systematically study the evolution of the upper and the lower kHz QPOs immediately before and after a Type-I TNB on 4U 1636$-$536 using {\it{AstroSat}} observations in the 3--20 keV band. The analysis of the power-density-spectra show the presence of kHz QPOs within 200 seconds before the onset of the Type--I burst. However, we have not detected any prominent signature of the same within 100-200 second posterior to the burst. The kHz QPOs then re-emerges after $\approx$ 200 sec. The fractional rms variation in the 3--20 keV band drops by $\approx$ 5-6 \%, supporting the non-existence of kHz QPOs in the 200 sec post-Burst Zone. The time scale of 200 sec coincides with the viscous time scale, highlighting a scenario where the inner disk is temporarily disrupted by the intense radiation from the Type-I TNB. The kHz QPO then re-establishes as the inner disk is restored.
Suchismito Chattopadhyay、Jaiverdhan Chauhan、Ranjeev Misra、Anne Lohfink、Rhaana Starling、Priya Bharali、Soma Mandal
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Suchismito Chattopadhyay,Jaiverdhan Chauhan,Ranjeev Misra,Anne Lohfink,Rhaana Starling,Priya Bharali,Soma Mandal.QPO signatures of disk restoration after type-I X-ray bursts from 4U~1636$-$536[EB/OL].(2025-05-02)[2025-07-17].https://arxiv.org/abs/2505.01291.点此复制
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