New results with Swift on Supergiant Fast X-ray Transients

TL;DR

This paper presents recent Swift observations of Supergiant Fast X-ray Transients, revealing their long-term properties, spectral behaviors, and temporal patterns, enhancing understanding of this new class of high-mass X-ray binaries.

Contribution

It provides the first detailed long-term monitoring data and spectral analysis of SFXTs, expanding knowledge of their behavior and characteristics.

Findings

Determined duty cycles of SFXTs.

Characterized spectral properties during outbursts.

Observed temporal variability and flare activity.

Abstract

We report here on the most recent results obtained on a new class of High Mass X-ray Binaries, the Supergiant Fast X-ray Transients. Since October 2007, we have been performing a monitoring campaign with Swift of four SFXTs (IGRJ17544-2916, XTEJ1739-302, IGRJ16479-4514 and the X-ray pulsar AXJ1841.0-0536) for about 1-2 ks, 2-3 times per week, allowing us to derive the previously unknown long term properties of this new class of sources (their duty cycles, spectral properties in outbursts and out-of-outbursts, temporal behaviour). We also report here on additional Swift observations of two SFXTs which are not part of the monitoring: IGRJ18483-0311 (observed with Swift/XRT during a whole orbital cycle) and SAXJ1818.6-1703 (observed for the first time simultaneously in the energy range 0.3-100 keV during a bright flare).