Unveiling the mystery of supergiant fast x-ray transients with XMM-Newton

Supergiant Fast Xray Transients are a subclass of supergiant fast Xraytransients and are among the most variable hard Xray sources in our galaxy.They are believed to host neutron stars with superstrong magnetic fields (i.e.,magnetars ) or supergiant stars with extremely clumpy winds. In order todistinguish between these possibilities, we propose here a continuation of ourfruitful study of SFXT in quiescence by carrying out two 40 ks XMM observationsof XTE J1743363 and IGR J174072808 in quiescence. These are the only two SFXTsnever observed with a high sensitivity Xray telescope. Studying the spectraland timing properties of the SFXT sources in quiescence proved so far to becrucial in order to test the applicability of current theoretical models proposed to interpret their behavior. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]