Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the nature of QPO phase lags in black hole candidates   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. 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 provides a feedback on the
emerging spectrum. We demonstrate that the QPO waveform is presented by the
product of a perturbation and a time delayed response factors, where the
response is energy dependent. The essential property of this effect is its
non-linear 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 signal in different energy
bands. We apply our model to QPOs observed by 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 to the nature
of the power law spectral component and its variability.

29
The categories of this paper are: funct-an
13
The categories of this paper are: quant-ph
4
The categories of this paper are: cond-mat
30
The categories of this paper are: q-alg
10
The categories of this paper are: q-bio
20
The categories of this paper are: acc-phys
2
The categories of this paper are: math
24
The categories of this paper are: dg-ga
27
The categories of this paper are: comp-gas
35
The categories of this paper are: mtrl-th
19
The categories of this paper are: eess
28
The categories of this paper are: alg-geom
11
The categories of this paper are: hep-lat
21
The categories of this paper are: adap-org
22
The categories of this paper are: chao-dyn
3
The categories of this paper are: physics