1120034

Investigating the poorly understood accretion mechanism producing the short flares observed from the SFXTs is a key tool in placing these X-ray binaries in the wider context of the HMXBs. Studies of this X-ray binary class are fundamental to understanding the evolution of massive stars to determining the chemical enrichment of the Galaxy and to give a significant contribution to studying the neutron star equation of the state. Current theories are based on a mass transfer via an isotropic and inhomogeneous clumpy wind or via accretion from anisotropic supergiant wind or on the high magnetic field of neutron stars (>10^14 G) regulating the duration and peak luminosity of the outbursts.Outbursts of IGR J16328-4726 occur at a restricted phase range (likely near to the periastron passage) of its orbital period (10.0680.002 days) allowing us to predict them and to plan pointed observations. We propose two short (~20ks) XMM-Newton observations simultaneous with long (200 ks) INTEGRAL observations performed at periastron.Using both XMM-Newton and INTEGRAL instruments we will measure the instantaneous accretion rate the broad band spectral shape and the absorption column density local to the source. These simultaneous observations will provide us with the best opportunity to know the circumstellar wind environment needed to discriminate between different physical mechanisms proposed to explain SFXTs. [truncated! Please see actual data for full text]