All Figures

$\begin{figure} \par\includegraphics[width=8.5cm,clip]{h3881f1.eps} \end{figure}$ Figure 1: The color-intensity diagram of GX 340+0. Dashed line polygons show the regions at the Horizontal and upper half of the Normal Branch used for the frequency resolved analysis.
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In the text

$\begin{figure} \par\includegraphics[width=8.2cm,clip]{h3881f2.eps} \end{figure}$ Figure 2: Power spectrum of GX 340+0 at the upper part of the Horizontal Branch of the color-intensity diagram.
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In the text

$\begin{figure} \par\hbox{ \includegraphics[width=8.5cm,clip]{h3881f3l.eps}\vspace*{2mm} \includegraphics[width=8.5cm,clip]{h3881f3r.eps} } \end{figure}$ Figure 3: The low ( left) and high ( right) frequency parts of the power spectrum of 4U1608 averaged over all data used for analysis. The power spectrum of the high frequency part, showing two kHz QPO peaks was obtained by "shift-and-add'' method.
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In the text

$\begin{figure} \par\includegraphics[width=8.5cm,clip]{h3881f4.eps} \end{figure}$ Figure 4: Average and frequency resolved spectra of GX 340+0 in the Horizontal Branch (Z=0-1, see Fig. 1). The solid lines show the Comptonized emission spectrum rescaled to match the frequency resolved spectra and the high energy part of the average spectrum. The parameters of the Comptonized spectrum are best fit to the frequency resolved spectrum of the $\sim$ 25 Hz QPO (Table 2).
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In the text

$\begin{figure} \par\includegraphics[width=8.5cm,clip]{h3881f5.eps} \end{figure}$ Figure 5: GX 340+0. Ratios of the frequency resolved spectra in various Fourier frequency bands to that of the 16-32 Hz band, corresponding to the Horizontal branch QPO. The data are from the Horizontal Branch of the color-intensity diagram (Z=0-1), i.e. the same as in Fig. 4. Note that the vertical scale is different in different panels.
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In the text

$\begin{figure} \par\includegraphics[width=8.5cm,clip]{h3881f6.eps} \end{figure}$ Figure 6: Phase lags for GX 340+0 in the Horizontal Branch of the color-intensity diagram (Z=0-1) as function of energy ( upper panel) and Fourier frequency ( lower panel). The energy dependent phase lags were computed in the 1-32 Hz frequency range, the frequency dependent lags are between 3-6.5 keV and 6.5-13 keV energy bands. The phase is normalized to 0-1 interval.
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In the text

$\begin{figure} \includegraphics[width=8.5cm,clip]{h3881f7u.eps}\par\includegraphics[width=8.5cm,clip]{h3881f7l.eps}\par \end{figure}$ Figure 7: Upper panel: Average and frequency resolved spectra of 4U1608-52. The solid lines show Comptonized disk spectra rescaled to match the frequency resolved spectra and the high energy part of the average spectrum. The parameters of the Comptonization spectrum are the best fits to the frequency resolved spectrum of the lower kHz QPO (Table 2). Lower panel: Ratios of the spectra shown in the upper panel to the spectrum of lower kHz QPO.
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In the text

$\begin{figure} \par\includegraphics[width=8.3cm,clip]{h3881f8.eps} \end{figure}$ Figure 8: GX 340+0: Coherence between the light curves in the 3-6.5 and 6.5-13 keV energy bands as function of frequency. No correction for the dead time effects has been made.
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In the text

$\begin{figure} \par\hbox{ \includegraphics[width=8.5cm,clip]{h3881f9a.eps}\hspac... ...\hspace*{0.7cm} \includegraphics[width=8.5cm,clip]{h3881f9d.eps} }\end{figure}$ Figure 9: The average and frequency resolved spectra of GX 340+0 ( left) and 4U1608-52 ( right). The GX 340+0 data are from horizontal branch of the color-intensity diagram, i.e. the same as used before. The shaded area shows a plausible range of the boundary layer spectral shape calculated subtracting the predicted disk spectrum from the total spectrum and renormalizing the residual to the total energy flux of the frequency resolved spectrum (see Sect. 5.2 and Table 1 for details). The dashed histogram shows the accretion disk spectrum with parameters from Table 2 (Sect. 5.3), the upper solid histogram shows the difference between the total and accretion disk spectrum ( $\approx$ boundary layer spectrum). The lower solid histogram is the same but scaled to the total energy flux of the frequency resolved spectrum. The lower panels show ratio of the frequency resolved spectrum to the lower histogram.
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In the text

$\begin{figure} \par\includegraphics[width=8.3cm,clip]{h3881f10.eps} \end{figure}$ Figure 10: The energy dependence of the fractional rms of the kHz QPO in 4U1608-52. Flattening above $\sim$ 10 keV indicates, that the energy spectrum of the oscillations at these energies has the same shape as the total spectrum.
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In the text

$\begin{figure} \par\includegraphics[width=6.8cm,clip]{h3881f11a.eps}\par\include... ...h3881f11b.eps}\par\includegraphics[width=6.8cm,clip]{h3881f11c.eps} \end{figure}$ Figure 11: The absorption corrected average ( upper panel), frequency resolved ( $\approx$ boundary layer, middle) and accretion disk ( lower) spectra of GX 340+0 and 4U1608-52. The solid, dashed and dotted lines in the upper panel show the best fit total, boundary layer and accretion disk spectra. The thin solid lines in the middle panel are best fit Comptonized spectra, the thick grey line is Wien spectrum with kT=2.1 keV. The frequency resolved spectra are normalized to the same energy flux. The solid lines in the lower panel show best fit spectra of the accretion disk, the dashed line is 4U1608-52 spectrum multiplied by a factor of 12. See Table 2 for values of the spectral parameters.
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In the text

$\begin{figure} \par\includegraphics[width=8.5cm,clip]{h3881f12.eps} \end{figure}$ Figure 12: The absorption corrected frequency resolved spectra of QPO ( $\approx$ boundary layer emission) in GX 340 in the horizontal branch, Z=0-1 (lower $\dot{M}$ ) and upper half of the normal branch, Z=1-1.5 (higher $\dot{M}$ ). See Fig. 1 for specification of the regions in the color-intensity diagram. The horizontal branch data is same as in Figs. 4, 9 and 11. The solid line shows Wien spectrum with kT=2.4 keV.
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In the text

$\begin{figure} \par\includegraphics[width=8.5cm,clip]{h3881f13.eps} \end{figure}$ Figure 13: The power density spectra of GX 340+0 in the 3-7 keV energy range (horizontal branch, same data as in Figs. 4, 9 and 11). The histogram with the error bars show power spectra of total, disk and boundary layer emission, obtained using the procedure described in Sect. 6; the straight solid line shows a power law $P(f)=3.5\times 10^{-5}\times f^{-1}$ . The power density is shown in units of fractional rms per Hz and all three spectra are normalized to the total count rate in the 3-7 keV band. Note, that the lower-most frequency bin is affected by the windowing effects, suppressing the power.
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In the text

$\begin{figure} \par\includegraphics[width=8.5cm,clip]{h3881f1.eps} \end{figure}$	Figure 1: The color-intensity diagram of GX 340+0. Dashed line polygons show the regions at the Horizontal and upper half of the Normal Branch used for the frequency resolved analysis.
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$\begin{figure} \par\includegraphics[width=8.2cm,clip]{h3881f2.eps} \end{figure}$	Figure 2: Power spectrum of GX 340+0 at the upper part of the Horizontal Branch of the color-intensity diagram.
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$\begin{figure} \par\hbox{ \includegraphics[width=8.5cm,clip]{h3881f3l.eps}\vspace*{2mm} \includegraphics[width=8.5cm,clip]{h3881f3r.eps} } \end{figure}$	Figure 3: The low ( left) and high ( right) frequency parts of the power spectrum of 4U1608 averaged over all data used for analysis. The power spectrum of the high frequency part, showing two kHz QPO peaks was obtained by "shift-and-add'' method.
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$\begin{figure} \par\includegraphics[width=8.5cm,clip]{h3881f4.eps} \end{figure}$	Figure 4: Average and frequency resolved spectra of GX 340+0 in the Horizontal Branch (Z=0-1, see Fig. 1). The solid lines show the Comptonized emission spectrum rescaled to match the frequency resolved spectra and the high energy part of the average spectrum. The parameters of the Comptonized spectrum are best fit to the frequency resolved spectrum of the $\sim$ 25 Hz QPO (Table 2).
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$\begin{figure} \par\includegraphics[width=8.5cm,clip]{h3881f5.eps} \end{figure}$	Figure 5: GX 340+0. Ratios of the frequency resolved spectra in various Fourier frequency bands to that of the 16-32 Hz band, corresponding to the Horizontal branch QPO. The data are from the Horizontal Branch of the color-intensity diagram (Z=0-1), i.e. the same as in Fig. 4. Note that the vertical scale is different in different panels.
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$\begin{figure} \par\includegraphics[width=8.5cm,clip]{h3881f6.eps} \end{figure}$	Figure 6: Phase lags for GX 340+0 in the Horizontal Branch of the color-intensity diagram (Z=0-1) as function of energy ( upper panel) and Fourier frequency ( lower panel). The energy dependent phase lags were computed in the 1-32 Hz frequency range, the frequency dependent lags are between 3-6.5 keV and 6.5-13 keV energy bands. The phase is normalized to 0-1 interval.
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$\begin{figure} \par\includegraphics[width=8.3cm,clip]{h3881f8.eps} \end{figure}$	Figure 8: GX 340+0: Coherence between the light curves in the 3-6.5 and 6.5-13 keV energy bands as function of frequency. No correction for the dead time effects has been made.
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$\begin{figure} \par\includegraphics[width=8.3cm,clip]{h3881f10.eps} \end{figure}$	Figure 10: The energy dependence of the fractional rms of the kHz QPO in 4U1608-52. Flattening above $\sim$ 10 keV indicates, that the energy spectrum of the oscillations at these energies has the same shape as the total spectrum.
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