Based on observations obtained at the 1.5 m Loiano telescope, operated by the Bologna Astronomical Observatory.

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Present address:

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...1995)

In the magnetic phase convention which is used frequently in the literature, $\mbox{$\phi_{\rm mag}$ }=0.0$ is defined by the linear polarization pulse observed when the angle between the line of sight and the magnetic field line in the accretion column is closest to $90^{\circ }$ , or, alternatively, when the sign of the circular polarization is crossing zero.

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... region

This is not to be confused with the total accretion rate, which includes the regions of high local mass flow densities resulting in submerged shocks with consecutive soft X-ray emission. Matt et al. (2000) found an excess of the soft-to-hard X-ray luminosity $L_{\rm SX}/L_{\rm HX}=5.4$ .

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