Accretion column: from dawn till dusk

In spite of more than forty years of studies open questions remain on thestructure and physical properties of the emission regions of accreting Xraypulsars. Here, we propose to observe the transient Xray pulsar V0332+53 withtwo 20ks pointings during the decline of an outburst with XMMNewton and NuSTAR.These joint TOO observations will allow us to observe the source both in highand low luminosity states when the accretion regime and the emission region areexpected to drastically change. The unique sensitivity and broadband coverageoffered by a simultaneous XMM Newton/NuSTAR observations will allow a detailedspectral and timing analysis in both states. This is essential to constrain theproperties of the emission region and the critical luminosity. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]