We constructed the cumulative luminosity distributions of most supergiant fast X-ray transients (SFXTs) and the classical supergiant X-ray binary (SgXB) IGR J18027-2016 by taking advantage of the long term monitoring of these sources carried out with Swift /XRT (0.3-10 keV). Classical SgXBs are characterized by cumulative distributions with a single knee around ∼1036-1037 erg s−1, while all SFXTs are found to be significantly sub-luminous and the main knee in their distributions is shifted at lower luminosities (.1035 erg s−1). As the latter are below the sensitivity limit of large field of view instruments opearating in the hard X-ray domain (>15 keV), we show that a soft X-ray monitoring is required to reconstruct the entire profile of the SFXT cumulative luminosity distributions. The difference between the cumulative luminosity distributions of classical SgXBs and SFXTs is interpreted in terms of different wind accretion modes.
|Original language||English (US)|
|Journal||Proceedings of Science|
|State||Published - 2014|
|Event||10th INTEGRAL Workshop: "A Synergistic View of the High Energy Sky", Integral 2014 - Annapolis, United States|
Duration: Sep 15 2014 → Sep 19 2014
ASJC Scopus subject areas