Transient X-ray pulsar V0332+53: pulse phase-resolved spectroscopy and
  the reflection model
  We present the results of the pulse phase- and luminosity-resolved
spectroscopy of the transient X-ray pulsar V0332+53, performed for the first
time in a wide luminosity range (1-40)x10^{37} erg/s during a giant outburst
observed by the RXTE observatory in Dec 2004 - Feb 2005. We characterize the
spectra quantitatively and built the detailed "three-dimensional" picture of
spectral variations with pulse phase and throughout the outburst. We show that
all spectral parameters are strongly variable with the pulse phase, and the
pattern of this variability significantly changes with luminosity directly
reflecting the associated changes in the structure of emission regions and
their beam patterns. Obtained results are qualitatively discussed in terms of
the recently developed reflection model for the formation of cyclotron lines in
the spectra of X-ray pulsars.
