XMM-NewtonandSwiftobservations of XTE J1743-363

Abstract

XTE J1743-363 is a poorly known hard X-ray transient, which displays short and intense flares similar to those observed from supergiant fast X-ray transients. The probable optical counterpart shows spectral properties similar to those of an M8 III giant, thus suggesting that XTE J1743-363 belongs to the class of the symbiotic X-ray binaries class. In this paper we report on the first dedicated monitoring campaign of the source in the soft X-ray range with XMM-Newton and Swift /XRT. These observations confirmed the association of XTE J1743-363 with the previously suggested M8 III giant and the classification of the source as a member of the symbiotic X-ray binaries. In the soft X-ray domain, XTE J1743-363 displays a high absorption (~6 × 1022 cm-2) and variability on time scales of hundreds to few thousand seconds, typical of wind-accreting systems. A relatively faint flare (peak X-ray flux 3 × 10-11 erg/cm2/s) lasting ~4 ks is recorded during the XMM-Newton observation and interpreted in terms of the wind accretion scenario.