The 100-month Swift catalogue of supergiant fast X-ray transients

Context. Supergiant fast X-ray transients (SFXTs) are high mass X-ray, binaries (HMXBs) that are defined by their hard X-ray flaring behaviour. During these flares they reach peak luminosities of 10(36)-10(37) erg s(-1) for a few hours On the hard X-ray), which are much shorter ti mescales than those characterizing Be/X-ray binaries. Aims. We investigate the characteristics of bright flares (detections in excess of 5 sigma.) for a sample of SFXTs and their relation to the orbital phase. Methods. We have retrieved all Swift/BAT Transient Monitor light curves and collected all detections in excess of 5 sigma from both dailyand orbital-averaged light curves in the time range of 2005 February 12 to 2013 May 31 (MID 53 413-56 443). We also considered all on-board detections as recorded in the same time span and selected those in excess of 5cr and within 4 arcmin of each source in our sample. Results. We present a catalogue of over a thousand BAT flares from 11 SIATs, down to 15-150 keV fluxes of similar to 6 x 10(-1) erg cm(-2) S-1 (daily timescale) and similar to 1.5 x 10(-9) erg cm(2) s(-1) (orbital timescale, averaging similar to 800 5); the great majority of these :flares are unpublished. The catalogue spans 100 months. This population is characterized by short (a few hundred seconds) and relatively bright (in excess of 100 mCrab, 15-50 keV) events. In the hard X-ray, these flares last generally much less than a day. Clustering of hard X-ray flares can be used to indirectly measure the length of an outburst, even when the low-level emission is not detected. We construct the distributions of.flares, of their significance (in terms of sigma), and of their flux as a function of orbital phase to infer the properties of these binary systems. In particular, we observe a trend of clustering of flares at some phases as P-orb increases, which is consistent with a progression from tight circular or mildly eccentric orbits at short periods to wider and more eccentric orbits at longer orbital periods. Finally, we estimate the expected number of flares for a given source for our limiting flux and provide the recipe for calculating them for the limiting :flux of future hard X-ray observatories.