Unveiling the mystery of supergiant fast x-ray transients

Supergiant Fast Xray Transients (SFXT) are very variable high mass Xraybinaries in our galaxy. Two models have been proposed to interpret theirbehavior: (i)a gating mechanism, involving either the centrifugal barrier orultramagnetic neutron stars (magnetars); (ii)an extermely clumpy wind from thesupergiant companion. Here we propose to study the quiescent emission of threeSFXTs. By making a comparison between their quiescence and outburst spectra andsearching for pulsations and column density variations, we will test theapplicability of the above models. These sources might well provide the veryfirst opportunity to detect and study magnetars in binary systems. In any case,very crucial information will be obtained to test the prediction of modern theories of radiativelydriven winds. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]