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Title: ON THE NATURE OF QUASI-PERIODIC OSCILLATION PHASE LAGS IN BLACK HOLE CANDIDATES

Journal Article · · Astrophysical Journal Letters
 [1]
  1. Department of Astronomy, CRESST/University of Maryland, College Park, MD 20742 (United States)

Observations of quasi-periodic oscillations (QPOs) in X-ray binaries hold a key to understanding many aspects of these enigmatic systems. Complex appearance of the Fourier phase lags related to QPOs is one of the most puzzling observational effects in accreting black holes (BHs). In this Letter we show that QPO properties, including phase lags, can be explained in a framework of a simple scenario, where the oscillating media provide feedback on the emerging spectrum. We demonstrate that the QPO waveform is presented by the product of a perturbation and time-delayed response factors, where the response is energy dependent. The essential property of this effect is its nonlinear and multiplicative nature. Our multiplicative reverberation model successfully describes the QPO components in energy-dependent power spectra as well as the appearance of the phase lags between signals in different energy bands. We apply our model to QPOs observed by the Rossi X-Ray Timing Explorer in BH candidate XTE J1550-564. We briefly discuss the implications of the observed energy dependence of the QPO reverberation times and amplitudes on the nature of the power-law spectral component and its variability.

OSTI ID:
22047745
Journal Information:
Astrophysical Journal Letters, Vol. 752, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 2041-8205
Country of Publication:
United States
Language:
English