0920016

The mass transfer and accretion mechanisms in SFXTs are key questions to be answered in order to place the SFXTs in the wider context of HMXB systems. Current theories centre on mass transfer via isotropic but inhomogeneous (`clumpy) winds but some systems also show evidence of disk-like structures around the supergiant analogous to those seen in Be/X-ray binaries. We propose a campaign of periastron observations of 7 systems with known ephemeris using both XMM and INTEGRAL to measure the instantaneous accretion rate emission spectrum and periodic signals generated around and on the neutron star. Now that the orbital parameters of these SFXT are well-determined targeted continuous broad-band observations around periastron provide us with the best opportunity to use the (assumed) neutron star as a direct probe of the circumstellar wind environment. To achieve the goals outlined in this proposal we request ~1.7 Ms of INTEGRAL observations complemented with 140 ks of simultaneous XMM-Newton observatons. [truncated! Please see actual data for full text]