Determination of QPO properties in the presence of strong broad-band noise: a case study on the data of MAXI J1820+070

Abstract

Accurate calculation of the phase lags of quasi-periodic oscillations (QPOs) will provide insight into their origin. In this paper we investigate the phase lag correction method which has been applied to calculate the intrinsic phase lags of the QPOs in MAXI J1820+070. We find that the traditional additive model between BBN and QPOs in the time domain is rejected, but the convolution model is accepted. By introducing a convolution mechanism in the time domain, the Fourier cross-spectrum analysis shows that the phase lags between QPOs components in different energy bands will have a simple linear relationship with the phase lags between the total signals, so that the intrinsic phase lags of the QPOs can be obtained by linear correction. The power density spectrum (PDS) thus requires a multiplicative model to interpret the data. We briefly discuss a physical scenario for interpreting the convolution. In this scenario, the corona acts as a low-pass filter, the Green's function containing the noise is convolved with the QPOs to form the low-frequency part of the PDS, while the high-frequency part requires an additive component. We use a multiplicative PDS model to fit the data observed by Insight-HXMT. The overall fitting results are similar compared to the traditional additive PDS model. Neither the width nor the centroid frequency of the QPOs obtained from each of the two PDS models were significantly different, except for the r.m.s. of the QPOs. Our work thus provides a new perspective on the coupling of noise and QPOs.

13 pages, 8 figures

References in corpus (7)

• Modelling the behaviour of accretion flows in X-ray binaries
• A review of quasi-periodic oscillations from black hole X-ray binaries: observation and theory
• The corona contracts in a black-hole transient
• A Systematic Analysis of the Phase Lags Associated with the Type-C Quasi-periodic Oscillation in GRS 1915+105
• Modelling the cross-spectral variability of the black hole binary MAXI J1659-152 with propagating accretion rate fluctuations
• Correlations in Horizontal Branch Oscillations and Break Components in XTE J1701-462 and GX 17+2
• Evolution of the hot flow of MAXI J1543-564

Cited by in corpus (7)

• A detailed view of low-frequency quasi-periodic oscillation in the broadband 0.2-200 keV with Insight-HXMT and NICER
• A Phase-resolved View of the Low-frequency Quasiperiodic Oscillations from the Black Hole Binary MAXI J1820+070
• Hilbert-Huang Transform analysis of quasi-periodic oscillations in MAXI J1820+070
• The nature of an imaginary quasi-periodic oscillation in the soft-to-hard transition of MAXI J1820+070
• A broadband spectral-timing study of QPOs in the bright black hole X-ray binary Swift J1727.8-1613
• Timing analysis of the black-hole candidate Swift J1727.8-1613: detection of a dip-like feature in the high-energy cross spectrum
• Intermittent QPO properties of MAXI J1820+070 revealed by Insight-HXMT